Information on EC 1.10.3.3 - L-ascorbate oxidase

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The expected taxonomic range for this enzyme is: Eukaryota

EC NUMBER
COMMENTARY
1.10.3.3
-
RECOMMENDED NAME
GeneOntology No.
L-ascorbate oxidase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
mechanism: Cu2+ is reduced to Cu+, which is then reoxidized by oxygen
Cucurbita pepo condensa
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
intramolecular electron transfer from type I copper to type III copper is probably the rate-limiting step in enzyme catalysis
Cucurbita pepo medullosa
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
multiple displacement mechanism, enzyme exhibits enzymic memory
Cucurbita pepo condensa
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
rate determining step in the catalytic mechanism may involve protonation of an intermediate
Cucurbita pepo medullosa
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
binding mode of phenolic inhibitors and substrate to active site, binding site in a pocket near type I copper center
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
mechanism and rate constants
Cucurbita pepo medullosa
-
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
the transition from native dimer to the dimeric intermediate is characterized by the release of copper ions forming the tri-nuclear copper center located at the interface between domain 2 and 3 of each subunit
P37064
4 L-ascorbate + O2 = 4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
oxidation
-
-
-
-
redox reaction
-
-
-
-
reduction
-
-
-
-
PATHWAY
KEGG Link
MetaCyc Link
Ascorbate and aldarate metabolism
-
Metabolic pathways
-
SYSTEMATIC NAME
IUBMB Comments
L-ascorbate:oxygen oxidoreductase
A multicopper protein.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
AA oxidase
-
-
-
-
AA-ox
Cucurbita sp.
-
-
AAO
-
-
-
-
AAO
-
-
AOase
P37064
-
ASC oxidase
-
-
ascorbase
-
-
-
-
ascorbate dehydrogenase
-
-
-
-
ascorbate oxidase
-
-
-
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
Q5M5B4, Q5M5B5
-
ascorbate oxidase
P14133
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
P37064
-
ascorbate oxidase
Cucurbita sp.
-
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
J7GBJ3
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
-
-
ascorbate oxidase
Pleurotus ostreatus NFFA2
-
-
-
ascorbate oxidase
-
-
ascorbate oxidase
Q4VDN6
-
ascorbate oxidase
Solanum lycopersicum West Virginia 106
Q4VDN6
-
-
ascorbic acid oxidase
-
-
-
-
ascorbic acid oxidase
-
-
ascorbic acid oxidase
-
-
ascorbic acid oxidase
-
-
ascorbic acid oxidase
-
-
ascorbic oxidase
-
-
-
-
L-ascorbate:O2 oxidoreductase
-
-
-
-
L-ascorbic acid oxidase
-
-
-
-
oxidase, ascorbate
-
-
-
-
CAS REGISTRY NUMBER
COMMENTARY
9029-44-1
-
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
sp. HI-25
-
-
Manually annotated by BRENDA team
Acremonium HI-25
sp. HI-25
-
-
Manually annotated by BRENDA team
strain HI-25
-
-
Manually annotated by BRENDA team
mutant, T-DNA inserted into enzyme gene
-
-
Manually annotated by BRENDA team
induction of enzyme by wouding or treatment with cellulase or araquidonic acid
Swissprot
Manually annotated by BRENDA team
wild watermelon No. 1011171, and domesticated watermelon cv. Sanki
-
-
Manually annotated by BRENDA team
satsuma mandarin
-
-
Manually annotated by BRENDA team
gene AO1; variety reticulatus, F1 alpha hybrid, gene AO1
SwissProt
Manually annotated by BRENDA team
gene AO4; variety reticulatus, F1 alpha hybrid, gene AO4
SwissProt
Manually annotated by BRENDA team
cucumber, 3 molecular forms: monomer, dimer, tetramer
-
-
Manually annotated by BRENDA team
expressed in Nicotiana tabacum
SwissProt
Manually annotated by BRENDA team
Japanese cucumber, turnip
-
-
Manually annotated by BRENDA team
Cucumis sp.
-
-
-
Manually annotated by BRENDA team
var. jerimum caboclo
-
-
Manually annotated by BRENDA team
green zucchini
UniProt
Manually annotated by BRENDA team
medullosa
UniProt
Manually annotated by BRENDA team
subsp. pepo convar. giromontiina
-
-
Manually annotated by BRENDA team
Cucurbita pepo condensa
-
-
-
Manually annotated by BRENDA team
Cucurbita pepo condensa
5 molecular forms: monomer, tetramer, octamer, dodecamer, polymer
-
-
Manually annotated by BRENDA team
Cucurbita pepo condensa
yellow summer crookneck squash, presence of 5 isoenzymes
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
green zucchini squash
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
zucchini squash
-
-
Manually annotated by BRENDA team
Cucurbita sp.
probably a secretory glycoprotein
-
-
Manually annotated by BRENDA team
Cucurbita sp.
pumpkin, sp. Ebisu Nankin
-
-
Manually annotated by BRENDA team
cv. Jubilant, two anionic isozymes A1 and A2, two cationic isozymes C2 and C3, one Cd-actiated cationic isozyme C1
-
-
Manually annotated by BRENDA team
bottle gourd
-
-
Manually annotated by BRENDA team
LjAO1
UniProt
Manually annotated by BRENDA team
LjAO1; LjAO1
UniProt
Manually annotated by BRENDA team
cv. Keitt
-
-
Manually annotated by BRENDA team
cv. Xanthi
-
-
Manually annotated by BRENDA team
expression of enzyme gene in sense and antisense orientation
-
-
Manually annotated by BRENDA team
induction of enzyme by light or auxin, salicylic acid inhibits
Swissprot
Manually annotated by BRENDA team
strain NFFA2
-
-
Manually annotated by BRENDA team
Pleurotus ostreatus NFFA2
strain NFFA2
-
-
Manually annotated by BRENDA team
cv. Paloma
-
-
Manually annotated by BRENDA team
white mustard
-
-
Manually annotated by BRENDA team
Solanum lycopersicum West Virginia 106
-
UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
evolution
P37064
AOase occurs only in higher plants
evolution
-
AAO belongs to the large family of multicopper oxidases. AAO labelling in the cytosol, walls and chloroplasts of Chaetomorpha linum cells, whereas in angiosperms this enzyme is almost exclusively confined to the extracellular matrix, possible function of AAO in adaptation and functional evolution of its cellular location, overview
evolution
J7GBJ3
phylogenetic tree of plant ascorbate oxidases, overview
evolution
-
phylogenetic tree of plant ascorbate oxidases, overview
malfunction
-
a diminution in ascorbate oxidase activity affects carbon allocation and improves yield in tomato under water deficit, overview. RNAi knockout plants show increased fruit yield under three conditions where assimilate became limiting for wild-type plants: when fruit trusses are left unpruned, when leaves are removed or when water supply is limited. Several alterations in the transgenic lines can contribute to the improved yield and favour transport of assimilate from leaves to fruits in the ascorbate oxidase lines. RNAi lines show altered sink strength
malfunction
Solanum lycopersicum West Virginia 106
-
a diminution in ascorbate oxidase activity affects carbon allocation and improves yield in tomato under water deficit, overview. RNAi knockout plants show increased fruit yield under three conditions where assimilate became limiting for wild-type plants: when fruit trusses are left unpruned, when leaves are removed or when water supply is limited. Several alterations in the transgenic lines can contribute to the improved yield and favour transport of assimilate from leaves to fruits in the ascorbate oxidase lines. RNAi lines show altered sink strength
-
physiological function
-
AAO plays a major role in the initial phase (oxidation of L-ascorbic acid to dehydroascorbic acid) of vitamin C degradation in broccoli
physiological function
P37064
ascorbate oxidase is a blue multicopper oxidase that catalyses the four-electron reduction of dioxygen to water with concomitant one-electron oxidation of the reducing organic substrate
physiological function
-
ascorbate/dehydroascorbate play important roles in plant growth
physiological function
-
ascorbate oxidase is an apoplastic enzyme, which controls the redox state of the apoplastic ascorbate pool, effects of ascorbate oxidase on the apoplastic redox state, overview
physiological function
J7GBJ3
ascorbate oxidase catalyzes the oxidation of ascorbate to yield water. Enzyme overexpressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. High enzme expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of arbuscular mycorrhizal symbiosis. Key role of this gene/enzyme in both nodule and arbuscular mycorrhizal development and functioning. The enzyme might be part of the general mechanism regulating cell wall architecture
physiological function
J7GBJ3
the enzyme is involved in antioxidant and redox regulation, overview. The protein catalyzes a complex reaction, with the safe reduction of molecular oxygen into water, without the release of reactive oxygen species, like hydrogen peroxide, superoxide anion, which result from partial O2 reduction. Involvement of the enzyme in plant-microbe interaction
physiological function
-
the enzyme is involved in antioxidant and redox regulation, overview. The protein catalyzes a complex reaction, with the safe reduction of molecular oxygen into water, without the release of reactive oxygen species, like hydrogen peroxide, superoxide anion, which result from partial O2 reduction
physiological function
Solanum lycopersicum West Virginia 106
-
ascorbate oxidase is an apoplastic enzyme, which controls the redox state of the apoplastic ascorbate pool, effects of ascorbate oxidase on the apoplastic redox state, overview
-
metabolism
-
stability of total vitamin C in situ was strongly dependent on the plant maturity stage and the processing conditions applied
additional information
P37064
proposed catalytic model, structure-function relationship, overview. Intramolecular electron transfer from the type-l copper centre to the trinuclear copper centre
additional information
-
partially folded monomeric species might populate the energy landscape of the enzyme. The overall AAO stability is crucially controlled by a few quaternary interactions at the subunits' interface
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2 hydroquinone + O2
2 quinone + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
at pH 7.2
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita sp.
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
P14133
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
double displacement mechanism, so called enzymatic memory
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
substrate specificity: overview
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
low reaction rate with bilirubin
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
no appreciable activity with: p-phenylenediamine, Na2S2O3, glutathione and cysteine
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
anionic form of the substrate is an important requirement of the enzyme specificity
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
-
highly specific for ascorbic acid and a few of its analogs and O2
-
?
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita pepo condensa
-
no oxidation of hydroquinone
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita sp.
-
enzyme may play a key role in the regulation of cell expansion
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita sp.
-
possibly a kind of pathogenesis-related protein
-
?
2 L-ascorbate + O2 + 4 H+
2 monodehydroascorbate + 2 H2O
show the reaction diagram
-
formation of free radicals during the oxidation reaction by ascorbate oxidase, formation of free radicals during the oxidation reaction by ascorbate oxidase, determination of steady-state free radical concentration, overview
-
-
?
2,5-dichlorohydroquinone + O2
2,5-dichloroquinone + H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
-
-
2,5-dichlorohydroquinone + O2
2,5-dichloroquinone + H2O
show the reaction diagram
Cucurbita pepo condensa
-
oxidation rate approx. 1/12 that of ascorbic acid, pH 5.7
-
?
2,6-dichlorohydroquinone + O2
2,6-dichloroquinone + H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
-
2,6-dichlorohydroquinone + O2
2,6-dichloroquinone + H2O
show the reaction diagram
Cucurbita pepo condensa
-
oxidation rate approx. 1/12 that of ascorbic acid, pH 5.7
-
?
2,6-dichloroindophenol + O2
oxidized 2,6-dichloroindophenol + H2O
show the reaction diagram
-
2,6-dichloroindophenol is an effective electron-transfer mediator for the enzyme, while ferrocyanide and cytochrome c are poor mediators
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
Q4VDN6, -
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
J7GBJ3
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
Solanum lycopersicum West Virginia 106
Q4VDN6
-
-
-
?
5,6-ene-L-ascorbate + O2
5,6-ene-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
5,6-isopropylidene-L-ascorbate + O2
5,6-isopropylidene-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
5-methyl-5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid + O2
? + H2O2
show the reaction diagram
Pleurotus ostreatus, Pleurotus ostreatus NFFA2
-
-
-
-
?
5-methyl-5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid + O2
? + H2O2
show the reaction diagram
Pleurotus ostreatus, Pleurotus ostreatus NFFA2
-
-
-
-
?
5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid + O2
? + H2O2
show the reaction diagram
Pleurotus ostreatus, Pleurotus ostreatus NFFA2
-
-
-
-
?
5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid + O2
? + H2O2
show the reaction diagram
Pleurotus ostreatus, Pleurotus ostreatus NFFA2
-
-
-
-
?
6-amino-L-ascorbate + O2
6-amino-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
6-bromo-L-ascorbate + O2
6-bromo-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
6-deoxy-L-ascorbate + O2
6-deoxy-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
6-O-phenyl-L-ascorbate + O2
6-O-phenyl-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
6-S-phenyl-L-ascorbate + O2
6-S-phenyl-L-dehydroascorbate
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
chlorohydroquinone + O2
chloroquinone + H2O
show the reaction diagram
Cucurbita sp.
-
6% of activity with L-ascorbic acid
-
?
D-erythroascorbic acid + O2
? + H2O2
show the reaction diagram
Pleurotus ostreatus, Pleurotus ostreatus NFFA2
-
-
-
-
?
D-glucoascorbic acid + O2
D-glucodehydroascorbate + H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
?
D-isoascorbic acid + O2
2-dehydroisoascorbate + H2O
show the reaction diagram
-
-
-
?
D-isoascorbic acid + O2
2-dehydroisoascorbate + H2O
show the reaction diagram
Cucurbita pepo condensa
-
-
-
?
D-isoascorbic acid + O2
2-dehydroisoascorbate + H2O
show the reaction diagram
Cucurbita pepo medullosa
-
-
-
?
D-isoascorbic acid + O2
2-dehydroisoascorbate + H2O
show the reaction diagram
-
-
-
?
hydroxyhydroquinone + O2
hydroxyquinone + H2O
show the reaction diagram
Cucurbita pepo condensa
-
oxidation rate approx. 1/12 that of ascorbic acid, pH 5.7
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
P37064
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
-
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
Q5M5B4, Q5M5B5
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
metabolic regulation, overview
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
role of AO is regulation of cell division through controlled apoplastic Asc levels
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
the enzyme activity is up- or down-regulated in response to oxygen availability
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
Q5M5B4, Q5M5B5
the gene expression is transcriptionally regulated during fruit development and in response to hormonal cues associated with the control of cell growth and the stress response
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
aerobic oxidation of ascorbate to the unstable ascorbate free radical
the radical plays a role as an electron acceptor in plant growth including plasma membrane electron transport, cell elongation and cell wall metabolism, overview
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O2
show the reaction diagram
-
-
-
-
?
L-ascorbyl-6-palmitate + O2
L-dehydroascorbyl-6-palmitate
show the reaction diagram
-
36% of activity with L-ascorbate
-
?
L-ascorbyl-6-stearate + O2
L-dehydroascorbyl-6-stearate
show the reaction diagram
-
29% of activity with L-ascorbate
-
?
leuco 2,6-dichloroindophenol + O2
oxidized leuco 2,6-dichloroindophenol + H2O
show the reaction diagram
Cucurbita pepo condensa
-
oxidation to the blue quinoid dye at pH 5.7
-
?
additional information
?
-
-
cell wall-localized enzyme that catalyses the oxidation of ascorbate to the unstable radical monodehydroascorbate, which rapidly disproportionates to yield dehydroascorbate and ascorbate, and thus contributes to the regulation of the ascorbic acid redox state regulating the cell redox status
-
-
-
additional information
?
-
-
ascorbic acid interferes with the realtime measurement of neuronal NO, an important gaseous neurotransmitter, by use of diaminofluoresceins, which act as receptors for NO, ascorbic acid reduces N2O3, the reaction intermediate of NO oxidation, while dehydroascorbic acid competes with NO for the receptors, while ascorbic acid inhibits the binding between NO and diaminofluoresceins, overview
-
-
-
additional information
?
-
-
the active site binding pocket of ascorbate oxidase is specific for ascorbate10 and the electron transfer of ascorbate oxidase is strongly dependent on the nature of the electron donor, overview
-
-
-
additional information
?
-
-
the oxidative activity of ascorbate oxidase is dominated by the highly selective substrate-binding affinity based on electrostatic interaction beyond the one-electron redox potential difference between type 1 copper site of ascorbate oxidase and substrate
-
-
-
additional information
?
-
-
the enzyme might perform two types of free radical decay reaction, dismutation and oxidation
-
-
-
additional information
?
-
-
the active site binding pocket of ascorbate oxidase is specific for ascorbate10 and the electron transfer of ascorbate oxidase is strongly dependent on the nature of the electron donor, overview
-
-
-
additional information
?
-
-
the oxidative activity of ascorbate oxidase is dominated by the highly selective substrate-binding affinity based on electrostatic interaction beyond the one-electron redox potential difference between type 1 copper site of ascorbate oxidase and substrate
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita sp.
-
enzyme may play a key role in the regulation of cell expansion
-
-
2 L-ascorbate + O2
2 L-dehydroascorbate + 2 H2O
show the reaction diagram
Cucurbita sp.
-
possibly a kind of pathogenesis-related protein
-
?
2 L-ascorbate + O2 + 4 H+
2 monodehydroascorbate + 2 H2O
show the reaction diagram
-
formation of free radicals during the oxidation reaction by ascorbate oxidase
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
Q4VDN6, -
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
J7GBJ3
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
4 L-ascorbate + O2
4 monodehydroascorbate + 2 H2O
show the reaction diagram
Solanum lycopersicum West Virginia 106
Q4VDN6
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
P37064
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
metabolic regulation, overview
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
role of AO is regulation of cell division through controlled apoplastic Asc levels
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
the enzyme activity is up- or down-regulated in response to oxygen availability
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
Q5M5B4, Q5M5B5
the gene expression is transcriptionally regulated during fruit development and in response to hormonal cues associated with the control of cell growth and the stress response
-
-
?
L-ascorbic acid + O2
L-dehydroascorbic acid + H2O
show the reaction diagram
-
-
-
-
?
additional information
?
-
-
cell wall-localized enzyme that catalyses the oxidation of ascorbate to the unstable radical monodehydroascorbate, which rapidly disproportionates to yield dehydroascorbate and ascorbate, and thus contributes to the regulation of the ascorbic acid redox state regulating the cell redox status
-
-
-
COFACTOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
copper
Cucurbita pepo condensa
-
a multicopper protein, 6 atoms of copper per enzyme molecule
copper
-
10 copper atoms per enzyme molecule
copper
Cucurbita pepo condensa
-
-
copper
-
8 atoms of copper per enzyme molecule of 132000 Da
copper
Cucurbita pepo medullosa
-
8 atoms of copper per enzyme molecule of 140000 Da
copper
Cucurbita pepo medullosa
-
10-12 atoms of copper per enzyme molecule of 140000 Da
copper
Cucumis sativus, Cucurbita pepo medullosa
-
4 copper atoms per subunit, mononuclear blue copper in domain 3 and trinuclear copper between domain 1 and 3
copper
Cucurbita pepo medullosa
-
measurement of intramolecular electron transfer between type I and type III copper centers in the multi-copper enzyme
copper
Cucurbita pepo medullosa
-
each subunit has 4 copper atoms bound as mononuclear and trinuclear species, mononuclear copper representing the type I copper is located in the 3 domain
copper
Cucurbita pepo medullosa
-
8 atoms of copper per enzyme molecule of 140000 Da; native enzyme contains two type 1, two type 2 and four type 3 copper ions
copper
Cucurbita pepo medullosa
-
-
copper
Cucurbita pepo medullosa
-
electronic structure of blue copper sites; evidence that the coordination environment and electronic structure of the type 1 copper is similar to those of plastocyanin and azurin
copper
Cucurbita pepo medullosa
-
coordination environment of type 2 copper; type 2 copper may be part of the ascorbate binding site
copper
-
enzyme contains a set of 1 type I, 1 type II and a pair of type III copper ions at its active site; principal active site comprised of one type I, one type II and a pair of type III coppers
copper
-
8 atoms of copper per enzyme molecule of 140000 Da
copper
Cucurbita sp.
-
-
copper
-
enzyme contains type I, type II and type III copper atoms in the ratio 1/2/2, 4 copper atoms/enzyme
copper
-
-
copper
Cucurbita pepo medullosa
-
type I and trinuclear type II copper center
copper
-
the oxidative activity of ascorbate oxidase is dominated by the highly selective substrate-binding affinity based on electrostatic interaction beyond the one-electron redox potential difference between type 1 copper site of ascorbate oxidase and substrate
Cu2+
-
a multicopper oxidase, contains type 1 Cu2+, binding residues are His445, Cys507, His512, and Met517
Cu2+
P37064
essential for activity, a tri-nuclear copper center structure, a partial loss of tertiary structure has strong effects on copper
Cu2+
-
a plant blue-copper protein
Cu2+
-
a blue copper-containing oxidase
Cu2+
Q5M5B4, Q5M5B5
copper-containing enzyme; copper-containing enzyme
Cu2+
P37064
9 copper atoms per enzyme molecule. Each subunit has four copper atoms bound as mononuclear and trinuclear species. The mononuclear copper has two histidine, a cysteine and a methionine ligand and represents the type-l copper. It is located in domain 3. Binding structure analysis, copper site structures, detailed overview
NaCl
-
induces the ascorbate oxidase activity
Cu2+
-
a multicopper oxidase
additional information
-
no support of a metal in the enzyme
additional information
Cucurbita pepo medullosa
-
selective removal of copper with chelating agents, e.g. EDTA or N,N-diethyldithiocarbamate produces an inactive enzyme, CN- treatment gives fully copper-depleted apoform, indication that copper affects the enzyme stability but not the enzyme conformation
INHIBITORS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
3,4,5-hydroxybenzoic acid propyl ester
Cucurbita pepo condensa
-
-
3,4-Dichlorophenylserine
Cucurbita pepo condensa
-
-
8-hydroxyquinoline
Cucurbita pepo condensa
-
-
8-hydroxyquinoline
-
1 mM, 42% inhibition of enzyme from soluble fraction
Ag+
Cucurbita pepo medullosa
-
inhibition of intramolecular electron transfer, mechnanism
alpha-tocopherol
Cucurbita pepo condensa
-
-
Anthocyanin pigments
Cucurbita pepo condensa
-
-
-
Auxin analogs
Cucurbita pepo condensa
-
-
-
azide
Cucurbita pepo condensa
-
-
azide
Cucurbita pepo medullosa
-
competitive vs. ascorbate, noncompetitive vs. O2
azide
-
1 mM, 42% inhibition of enzyme from soluble fraction
azide
Cucurbita pepo medullosa
-
-
azide
-
8 mM, 28% inhibition; weak inhibition
azide
Cucurbita pepo medullosa
-
mixed-type inhibition above pH 6, competitive inhibition at pH 5.6; weak inhibition
azide
-
1 mM, complete inhibition
Carotenes
Cucurbita pepo condensa
-
-
-
Cd2+
-
cadmium-induced inhibition of apoplastic isozyme in barley roots, 50% inhibition of root growth at 1.0 mM 72 h after the treatment, root growth inhibition due to excess Cd is accompanied by a corresponding loss of plasma membrane integrity in root cells, cationic isozyme C1 is activated by Cd2+
citrate
Cucurbita pepo condensa
-
univalent anion, competitive vs. ascorbate
Cu2+
Cucurbita pepo condensa
-
-
Cupferron
Cucurbita pepo condensa
-
-
cyanide
-
very slight
cyanide
Cucurbita pepo condensa
-
-
cyanide
Cucurbita pepo medullosa
-
-
cyanide
Cucurbita pepo condensa
-
0.001 mM, 50% inhibition of ascorbic acid and 2,6-dichloroindophenol oxidation
cyanide
-
complete inhibition
cyanide
-
1 mM, 57% inhibition
deoxycorticosterone
Cucurbita pepo condensa
-
-
diethyldithiocarbamate
Cucurbita pepo condensa
-
-
diethyldithiocarbamate
-
1 mM, 75% inhibition of enzyme from soluble fraction, 60% inhibition of enzyme from cell-wall preparatin
diethyldithiocarbamate
Cucurbita pepo condensa
-
0.0001 mM, 50% inhibition of ascorbic acid and 2,6-dichloroindophenol oxidation
diethyldithiocarbamate
-
complete inhibition
ethyl xanthate
Cucurbita pepo condensa
-
-
F-
Cucumis sativus, Cucurbita pepo condensa
-
-
F-
Cucurbita pepo medullosa
-
competitive vs. ascorbate, noncompetitive vs. O2
F-
Cucurbita pepo medullosa
-
-
F-
Cucurbita pepo medullosa
-
mixed-type inhibition above pH 5.6
Fe3+
-
1 mM, 91% inhibition
-
Fenton's reagent
-
Fe2+ + H2O2 + 2 H+
H2O2
-
inhibition at 5.6 mM, stimulation at 0.56 mM
H2O2
Cucurbita pepo condensa
-
-
H2S
Cucurbita pepo condensa
-
-
H2S
-
1 mM, 97% inhibition
Hg2+
Cucurbita pepo condensa
-
0.01 mM, appreciable inhibition
iodoacetate
Cucurbita pepo condensa
-
-
leucocyanidol
Cucurbita pepo condensa
-
-
Ni2+
Cucurbita pepo condensa
-
some authors found inhibition, others not
Nitrofurantoin
-
slight
nordihydroguaiaretic acid
Cucurbita pepo condensa
-
-
o-fluorophenol
-
-
Organic mercurials
Cucurbita pepo condensa
-
-
-
p-chlorophenol
Cucurbita pepo medullosa
-
-
p-Cresol
Cucurbita pepo medullosa
-
-
p-cyanophenol
Cucurbita pepo medullosa
-
-
p-fluorophenol
-
-
p-mercuribenzoate
Cucurbita pepo condensa
-
some authors report inhibition, others do not
p-nitrophenol
Cucurbita pepo medullosa
-
-
Phenol
Cucurbita pepo medullosa
-
-
Piperazine N,N'-bis(2-ethanesulfonic acid)
Cucurbita pepo condensa
-
anions
Pyridine-KNCS
Cucurbita pepo condensa
-
-
-
Salicylaldoxime
Cucurbita pepo condensa
-
-
SO2
Cucurbita pepo condensa
-
-
Tetraethylthiuramidisulfide
Cucurbita pepo condensa
-
-
thiamine
Cucurbita pepo condensa
-
-
Thiocyanate
Cucurbita pepo medullosa
-
weak inhibition, mixed-type inhibition
Thiourea
Cucurbita pepo condensa
-
-
Thiourea
-
300 mM, 55% inhibition
Urea
Cucumis sativus, Cucurbita pepo condensa
-
effect on various molecular forms
Zn2+
Cucurbita pepo condensa
-
some authors found inhibition, others not
Metabisulfite
-
complete inhibition
additional information
-
reaction inactivation: progressive loss of activity during oxidation of ascorbic acid, not inhibited by diethyldithiocarbamate
-
additional information
Cucurbita pepo condensa
-
natural inhibitors: cabbage extract, tomato extract, strawberry juice, extract of lemons, oranges, parsley, hips, leeks
-
additional information
-
the enzyme activity decreases during germination of under hypoxic conditions
-
additional information
-
drought conditions suppress the enzyme
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
2,2'-Bipyridyl
-
stimulation
ascorbate
Cucurbita pepo condensa
-
treatment with excess ascorbate at pH 4.85 to pH 5.5 in the presence of citrate and chloride and in the absence of O2, 9fold increase in maximal velocity
Cd2+
-
cadmium-induced inhibition of apoplastic isozyme in barley roots, cationic isozyme C1 is activated by Cd2+
CuCl2
-
1 mM, 2fold activation
ethanol
-
stimulation
far red light
-
7fold increase in activity after exposure to far red light for 36 h, suggesting post-translational control of activity by phytochrome
-
H2O2
-
stimulation at low concentration, 0.056 mM
iodoacetate
-
stimulation
o-phenanthroline
-
stimulation
p-chloromercuribenzoate
-
stimulation
light
-
required for activity, the activity is proportional to light intensity, the light effect is rapidly reversed in dark and activity remains low throughout the dark period
-
additional information
-
high light conditions induce the enzyme
-
additional information
Q5M5B4, Q5M5B5
AO4 expression is activated upon germination, and also regulated in response to wounding and heat stress, by hormones abscisic acid, salicylic acid and jasmonates, ascorbic acid and copper, overview
-
additional information
-
immobilization method using self-assembled monolayer and a polymer membrane mixed system is effective for the direct electron transfer reactions of not only native ascorbate oxidase, but also poly(ethylene oxide)-modified ascorbate oxidases
-
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
1.12
-
5,6-ene-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.554
-
5,6-isopropylidene-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.433
-
5-methyl-5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid
-
-
0.162
-
5-methyl-5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid
-
-
0.402
-
5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid
-
-
0.642
-
5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid
-
-
0.887
-
6-amino-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.124
-
6-bromo-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.187
-
6-deoxy-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.026
-
6-O-phenyl-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.032
-
6-S-phenyl-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.37
-
chlorohydroquinone
Cucurbita sp.
-
-
0.304
-
D-erythroascorbic acid
-
-
0.53
-
D-iso-ascorbate
-
-
1.307
-
D-isoascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.039
-
L-ascorbate
Cucurbita pepo condensa
-
spectrometric assay
0.1
0.35
L-ascorbate
Cucurbita pepo medullosa
-
free enzyme
0.12
-
L-ascorbate
Cucurbita pepo medullosa
-
enzyme in solution
0.132
-
L-ascorbate
Cucurbita pepo medullosa
-
activity in media of 10 days old cell culture treated with 0.004 mg/ml tunicamycin
0.14
-
L-ascorbate
Cucurbita pepo medullosa
-
enzyme embedded in silica matrix
0.147
-
L-ascorbate
Cucurbita pepo medullosa
-
activity in media of 10 days old cell culture
0.166
-
L-ascorbate
-
O2 consumption, polarographic method
0.18
-
L-ascorbate
-
free ascorbate oxidase, at pH 5.5 and 40C
0.181
-
L-ascorbate
-
spectrophotometric method
0.2
-
L-ascorbate
-
spectrophotometric assay
0.2
-
L-ascorbate
Cucurbita pepo condensa
-
spectrophotometric method
0.2
-
L-ascorbate
-
immobilized ascorbate oxidase, at pH 6.0 and 40C
0.204
-
L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.24
-
L-ascorbate
Cucurbita pepo condensa
-
spectrometric assay
0.262
-
L-ascorbate
Cucurbita pepo medullosa
-
-
0.29
-
L-ascorbate
-
-
0.3
-
L-ascorbate
-
-
0.42
-
L-ascorbate
Cucurbita pepo condensa
-
manomeric assay following the rate of O2 uptake
0.98
-
L-ascorbate
Cucurbita pepo condensa
-
Warburg method
1.125
-
L-ascorbate
-
Warburg method
2
-
L-ascorbate
Cucurbita pepo condensa
-
manomeric assay following the rate of O2 uptake
5
-
L-ascorbate
Cucurbita pepo condensa
-
manomeric assay following the rate of O2 uptake
10
-
L-ascorbate
-
enzyme from soluble fraction and cell-wall preparation
0.126
-
L-ascorbic acid
-
pH 6.0, 25C
0.338
-
L-ascorbic acid
-
-
0.47
-
O2
-
-
1.5
-
L-ascorbic acid
Cucurbita sp.
-
-
additional information
-
additional information
Cucurbita pepo medullosa
-
Km of the native enzyme and various deglycosylated forms
-
additional information
-
additional information
Cucurbita pepo condensa
-
Km of ascorbate and O2 is insensitive to pH in the range of 5.0-8.5
-
additional information
-
additional information
Cucurbita pepo medullosa
-
-
-
additional information
-
additional information
-
Michaelis-Menten kinetics, and thermodynamics at 25-48 C, detailed overview
-
TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
639
-
5,6-ene-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
623
-
5,6-isopropylidene-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
0.55
-
5-methyl-5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid
-
-
0.24
-
5-methyl-5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid
-
-
0.6
-
5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid
-
-
1.29
-
5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid
-
-
546
-
6-amino-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
702
-
6-bromo-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
969
-
6-deoxy-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
473
-
6-O-phenyl-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
526
-
6-S-phenyl-L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
1.12
-
D-erythroascorbic acid
-
-
804
-
D-isoascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
7.6
-
L-ascorbate
Cucurbita pepo medullosa
-
-
682
-
L-ascorbate
Cucurbita pepo medullosa
-
commercial enzyme preparation from Sigma
3110
-
L-ascorbate
-
-
4170
-
L-ascorbate
Cucurbita pepo condensa
-
manometric assay
10800
-
L-ascorbate
Cucurbita pepo condensa
-
spectrometric assay
0.66
-
L-ascorbic acid
-
-
1130
-
O2
-
-
Ki VALUE [mM]
Ki VALUE [mM] Maximum
INHIBITOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.06
-
azide
-
at 1.5C
0.21
-
azide
-
at 25C
1
-
p-chlorophenol
Cucurbita pepo medullosa
-
at pH 7.0
18
-
p-Cresol
Cucurbita pepo medullosa
-
at pH 7.0
2
-
p-cyanophenol
Cucurbita pepo medullosa
-
at pH 7.0
2.5
-
p-nitrophenol
Cucurbita pepo medullosa
-
at pH 8.0
3
-
p-nitrophenol
Cucurbita pepo medullosa
-
at pH 7.0
3.6
-
p-nitrophenol
Cucurbita pepo medullosa
-
at pH 6.5
4.2
-
p-nitrophenol
Cucurbita pepo medullosa
-
at pH 6.0
4.6
-
p-nitrophenol
Cucurbita pepo medullosa
-
at pH 5.0
6
-
Phenol
Cucurbita pepo medullosa
-
at pH 7.0
SPECIFIC ACTIVITY [µmol/min/mg]
SPECIFIC ACTIVITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
133.5
310
Cucurbita sp.
-
different purified commercial preparations
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
4.5
-
-
-
4.5
-
-
ascorbate oxidation optimum
4.8
-
-
assay at
5.3
-
-
assay at
5.5
7
-
255% of the activity at pH 3.0
5.5
-
-
-
5.5
-
-
optimal pH of free ascorbate oxidase
5.6
-
Cucurbita pepo condensa
-
-
5.6
-
Cucurbita pepo medullosa
-
free and immobilized enzyme
5.6
-
-
assay at
5.8
7
-
assay at
5.8
-
-
electrophoretic assay at
6
-
-
enzyme from soluble fraction and cell-wall preparation
6
-
-
assay at
6
-
P37064
assay at
6
-
-
optimal pH of biosensor/immobilized ascorbate oxidase
6.2
-
-
basic enzyme
6.5
-
Cucurbita sp.
-
-
7.5
-
-
optimum for the electrochemical catalytic reaction
7.8
-
-
spectrophotometric assay at
7.9
-
-
assay at
pH RANGE
pH RANGE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
4.5
8.3
-
at pH 4.5 and 8.3: approx. 50% activity
5
9
-
free enzyme: approx. 60% activity at pH 5.0, less than 10% activity at pH 9.0, immobilized enzyme: approx. 80% activity at pH 5.0, approx. 45% activity at pH 9.0
additional information
-
-
pH profile, overview
TEMPERATURE OPTIMUM
TEMPERATURE OPTIMUM MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
20
-
P37064
assay at
25
-
-
assay at
25
-
-
assay at
25
-
-
assay at
25
-
-
assay at
28
-
-
assay at
30
-
-
assay at
40
-
-
optimal pH of freee and biosensor/immobilized ascorbate oxidase
45
-
-
-
TEMPERATURE RANGE
TEMPERATURE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Cucurbita sp.
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Cucurbita sp.
-
different batches of commercially available crude enzyme from different suppliers, batch compositions, overview
Manually annotated by BRENDA team
-
broccoli florets show higher AAO activity compared to stalks
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Q9M685
bud of
Manually annotated by BRENDA team
Q5M5B4, Q5M5B5
high expression level of isozyme AO1
Manually annotated by BRENDA team
Cucumis sativus, Cucurbita pepo condensa
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Cucurbita sp.
-
-
Manually annotated by BRENDA team
Q5M5B4, Q5M5B5
high expression level of isozyme AO1, differential expression of the ascorbate oxidase multigene family during fruit development and in response to stress, overview
Manually annotated by BRENDA team
Solanum lycopersicum West Virginia 106
-
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
P14133
up to 380fold increase in enzyme activity of transgenic plant
Manually annotated by BRENDA team
-
second leaves
Manually annotated by BRENDA team
-
comparison of enzyme activity in leaves of wild and domesticated water melon, overview
Manually annotated by BRENDA team
-
total vitamin C content and L-ascorbate/dehydroascorbate ratio in leaves change at different stages of maturity. Young leaves likely contain a lower L-ascorbate/dehydroascorbate ratio than older leaves
Manually annotated by BRENDA team
-
homogenates of the mouth area
Manually annotated by BRENDA team
J7GBJ3
arbuscular, enzyme localization in the highly specialized structures at the host-symbiont interface
Manually annotated by BRENDA team
Cucurbita pepo condensa
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
-
root apex, particularly abundant in quiescent centre cells and differentiating vascular tissues, absent in lateral root primordia
Manually annotated by BRENDA team
J7GBJ3
LjAO1 expression is 12fold induced in mycorrhizal roots
Manually annotated by BRENDA team
J7GBJ3
endodermis, enzyme localization in the highly specialized structures at the host-symbiont interface
Manually annotated by BRENDA team
J7GBJ3
LjAO1 is induced during nodulation in Lotus japonicus and is expressed in the peripheral area of the nodule in a possible targeted mechanism controlling oxygen content
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
-
broccoli stalks show lower AAO activity compared to florets
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Q5M5B4, Q5M5B5
high expression level of isozyme AO4
Manually annotated by BRENDA team
Solanum lycopersicum West Virginia 106
-
-
-
Manually annotated by BRENDA team
additional information
Q9M685
almost no enzyme expression and activity in leaf
Manually annotated by BRENDA team
additional information
-
the enzyme activity decreases during germination of under hypoxic conditions, activity remains low throughout the dark period
Manually annotated by BRENDA team
additional information
-
the activity increases in the facultative CAM plant upon induction of the CAM cycle
Manually annotated by BRENDA team
additional information
-
the enzyme activity decreases during germination of under hypoxic conditions, the activity increases in the facultative CAM plant upon induction of the CAM cycle
Manually annotated by BRENDA team
additional information
Q5M5B4, Q5M5B5
differential expression of the ascorbate oxidase multigene family during fruit development and in response to stress, overview
Manually annotated by BRENDA team
additional information
-
algal filaments
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
Solanum lycopersicum West Virginia 106
-
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
-
predominantly, 60% of total activity
Manually annotated by BRENDA team
J7GBJ3
the enzyme is mostly present at the peripheral region of the cell wall, in close contact with the membrane
Manually annotated by BRENDA team
-
the enzyme is mostly present at the peripheral region of the cell wall, in close contact with the membrane
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
-
Manually annotated by BRENDA team
Cucurbita pepo medullosa
-
cultured cells
-
Manually annotated by BRENDA team
Cucurbita sp.
-
actively secreted during growth of cell suspension cultures; cultured cells
-
Manually annotated by BRENDA team
Cucurbita sp.
-
cultured cells
-
Manually annotated by BRENDA team
-
24% of total activity
-
Manually annotated by BRENDA team
-
16% of total activity
-
Manually annotated by BRENDA team
additional information
-
no activity in chloroplast
-
Manually annotated by BRENDA team
MOLECULAR WEIGHT
MOLECULAR WEIGHT MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
80000
-
-
-
132000
-
-
sedimentation equilibrium
132000
-
Cucurbita pepo medullosa
-
gel filtration
139000
-
-
basic enzyme, gel filtration
140000
-
-
-
140000
-
Cucurbita pepo medullosa
-
sedimentation equilibrium and difussion studies
140000
-
-
gel filtration
140000
-
Cucurbita pepo medullosa
-
-
140000
-
-
acidic enzyme, gel filtration
141000
-
-
gel filtration
150000
-
-
gel filtration
SUBUNITS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
?
-
x * 62258, deduced from amino acid sequence
?
Cucurbita sp.
-
x * 61268, deduced from amino acid sequence; x * 64000, SDS-PAGE
dimer
Cucurbita pepo medullosa
-
2 * 70000, 70000 Da subunit consists of 2 polypeptide chains of 30000 and 40000 Da respectively
dimer
-
2 * 30000, enzyme exists as monomer, dimer and tetramer, SDS-PAGE
dimer
Cucurbita pepo medullosa
-
2 * 65000, treatment with 2-mercaptoethanol results in 2 new bands, an A chain of 38000 Da and an B chain of 28000 Da, SDS-PAGE
dimer
-
1 * 74000 + 1 * 62000, SDS-PAGE
dimer
-
2 * 72000, basic enzyme, SDS-PAGE
dimer
P37064
unfolding studies, pressure-induced and denaturing agents-induced dissociation and unfolding, and the role of dimerization in the folding strategy of a large protein, crystal structure analysis, physico-chemical properties of a molten dimer enzyme, three distinct domains per subunit, sharing a common beta-barrel topology, overview
dodecamer
Cucurbita pepo condensa
-
12 * 35000, enzyme exists as monomer, tetramer, octamer, dodecamer and polymer, SDS-PAGE
homodimer
-
ascorbate oxidase is a large, multidomain, dimeric protein
monomer
-
1 * 30000, enzyme also exists as dimer and tetramer, SDS-PAGE
monomer
Cucurbita pepo condensa
-
1 * 35000, enzyme also exists as tetramer, octamer, dodecamer and polymer, SDS-PAGE
monomer
-
1 * 80000
octamer
Cucurbita pepo condensa
-
8 * 35000, enzyme exists as monomer, tetramer, octamer, dodecamer and polymer, SDS-PAGE
polymer
Cucurbita pepo condensa
-
x * 35000, between 670000 Da and 2000000 Da, enzyme exists as monomer, tetramer, octamer, dodecamer and polymer, SDS-PAGE
tetramer
-
4 * 30000, enzyme exists as monomer, dimer and tetramer, SDS-PAGE
tetramer
Cucurbita pepo condensa, Cucurbita pepo medullosa
-
4 * 35000, enzyme exists as monomer, tetramer, octamer, dodecamer and polymer, SDS-PAGE
tetramer
P37064
4 * 70000, tetramer with D2 symmetry, crystal structure and SDS-PAGE, present as dimer in solution. Each subunit is built up by three domains arranged sequentially on the polypeptide chain and tightly associated in space. The folding of all three domains is of a similar beta-barrel type, analysis of intra- and intertetramer hydrogen bond and van der Waals interactions, domains structures, detailed overview
monomer
Acremonium HI-25
-
1 * 80000
-
additional information
Cucurbita pepo medullosa
-
each subunit is devided into 3 domains
additional information
Cucurbita pepo medullosa
-
quarternary structure
additional information
-
structure analysis: the monomers keep their secondary structure, whereas subtle conformational changes in the tertiary structure become apparent, salt bridges and electrostatic interactions occurring at the dimeric interface play a crucial role in the stabilization of the monomer's tertiary structure., folding/unfolding pathway, overview. Each subunit is formed by three distinct domains and contains four copper ions, three of which are located at the interface between domains, forming a so-called trinuclear centre
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
glycoprotein
-
11.2% carbohydrate
glycoprotein
P37064
Asn92 is the attachment site for one of the two N-linked sugar moieties, which has defined electron density for the N-linked N-acetylglucosamine ring. Three putative attachment sites for N-glycosidiclinked carbohydrate moieties are present in the amino acid sequence of AOase from Zucchini, i.e. Asn92-Phe93-Thr94, Asn325-Phe326-Thr327, and Asn440-Leu441 -Ser442, but only Asn92 shows density for an N-acetyl-glucosamine group
glycoprotein
Cucurbita pepo condensa
-
enzyme may be a protein-copper carbohydrate complex
glycoprotein
Cucurbita pepo medullosa
-
2.4% carbohydrate
glycoprotein
Cucurbita pepo medullosa
-
enzyme contains 3% carbohydrates, deglycosylation studies
glycoprotein
Cucurbita pepo medullosa
-
a poorly glycosylated enzyme is produced in cell cultures treated with 0.004 mg/ml tunicamycin that is more active than the native enzyme
glycoprotein
Cucurbita sp.
-
4 possible N-glycosylation sites
Crystallization/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
fully oxidized form of ascorbate oxidase, X-ray diffraction structure determination and analysis at 1.90 A resolution
P37064
15 mg/ml enzyme solution, dialysis with 10% 2-methyl-2,4-pentanediol in 50 mM phosphate buffer, pH 5.4 at 4C, crystals suitable for X-ray studies, 2.5 A resolution
Cucurbita pepo medullosa
-
vapour diffusion method, 1.9 M sodium-potassium phosphate buffer pH 7.0 as reservoir solution at 4C, final protein concentration 5-6 mg/ml
Cucurbita pepo medullosa
-
X-ray crystal structure at 2.5 A resolution
Cucurbita pepo medullosa
-
pH STABILITY
pH STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
3.6
-
Cucurbita pepo medullosa
-
loss of 80% activity after 30 min at 0C
4
-
Cucurbita pepo condensa
-
irreversible loss of activity below
5
10
Cucurbita sp.
-
rapid loss of activity below pH 4 and above pH 12
6
10
-
at 30C
TEMPERATURE STABILITY
TEMPERATURE STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
0
40
-
30 min, stable
10
-
-
half-life: 1047 min
12
-
Cucurbita pepo medullosa
-
stable for at least 30 days
15
-
-
immobilized enzyme retains full activity for 3 months at pH 5.0-7.0, free enzyme looses 40-70% activity within one day at pH 5.0-7.0
40
50
Cucumis sativus, Cucurbita pepo condensa
-
conversion of octamer and heavier forms to a dimer
40
-
-
stable for 30 min
50
80
-
during thermal treatments for 10 min, AAO in broccoli florets and stalks is stable until around 50C. A 10 min thermal treatment at 80C almost completely inactivates AAO. AAO inactivation is irreversible since no increase in activity is observed when extracts of thermal treated broccoli are stored at 4C for 24 h
50
-
-
stable for 5 min
55
-
Cucurbita sp.
-
no loss in activity after 30 min, approx. 55% activity after 30 min at 60C, approx. 30% activity after 30 min at 65C
60
-
-
free enzyme: 20 min, 90% loss of activity, immobilized enzyme: 10% loss of activity
60
-
-
stable for 30 min
70
-
-
half-life: 21.2 min
80
-
Cucurbita pepo medullosa
-
-
80
-
Cucurbita pepo medullosa
-
10 min, complete loss of activity
90
-
-
thermal inactivation of AAO follows first-order reaction kinetics. Heating at temperatures above 90C for short times results in a complete AAO inactivation, resulting in a protective effect of L-ascorbic acid toward enzyme-catalyzed oxidation
100
-
-
complete inactivation after 1 min
100
-
Cucumis sativus, Cucurbita pepo condensa
-
1 min, all forms of enzyme inactivated
additional information
-
Cucurbita pepo medullosa
-
role of copper in heat stability
additional information
-
Cucumis sativus, Cucurbita pepo condensa
-
different molecular forms vary in resistance to heat inactivation: tetramer of squash and dimer of cucumber being most resistant
additional information
-
Cucurbita pepo medullosa
-
-
additional information
-
-
the thermal inactivation is irreversible, a first-order reaction mechanism
additional information
-
-
enzyme thermal stability in freshly harvested 4, 6, or 8 weeks old leaves and in leaves of the same ages stored at -80C and thawed at 25C, overview. In situ thermal inactivation of AAO in cowpea leaves follows first-order kinetics with an Arrhenius dependence
GENERAL STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
ascorbate oxidase is alternately deposited with Au nanoparticles and forms a layer-by-layer membrane on a Pt electrode. The enzyme activities remain even after the deposition. The oxidation current of ascorbic acid (0.1 mM) decreases to 36% for the (ascorbate oxidase/Au)1 modified electrode, and to 19% for the (ascorbate oxidase/Au)10 modified electrode
Cucumis sp.
-
immobilization within 6% Ca-alginate gel beads improves stability
-
partially unfolding of the enzyme by 1.4 M guanidinium hydrochloride or 2.8 M urea
P37064
gelatin, catalase, peroxidase and methemoglobin protect against inactivation
Cucurbita pepo condensa
-
20-25% retention of activity after immobilization, at 12C, stable for at least 30 days
Cucurbita pepo medullosa
-
no change in total activity in the presence of 5 M urea, conversion of tetrameric form into monomer with 75% activity in 8 M urea
Cucurbita pepo medullosa
-
role of copper in stability
Cucurbita pepo medullosa
-
a long acting enzyme derivative is synthesized by covalently linking poly(ethylene glycol) to the enzyme
Cucurbita sp.
-
stable to dialysis against EDTA or cyanide
-
OXIDATION STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
comparison of tolerance of wild-type and transgenic tobacco plants to oxidative stress, overview
-
675145
STORAGE STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
12C, at least 30 d, no loss of activity
Cucurbita pepo medullosa
-
4C, 10 months, no loss in activity
Cucurbita pepo medullosa
-
4C, 2 months, 20% loss of activity
Cucurbita pepo medullosa
-
4C, concentrated solution, 3 months, 20% loss of activity
Cucurbita pepo medullosa
-
-20C, purified commercial enzymes, 10 mM HEPES-NaOH, pH 8.0, and 60% sucrose, comparison of the stability of the different enzyme batches, overview
Cucurbita sp.
-
4C, ascorbate oxidase immobilized onto egg shell membrane through glutaraldehyde coupling in 0.1 M sodium phosphate EDTA buffer pH 5.6, 120 days, 50% loss of activity
-
Purification/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
recombinant wild-type enzyme and various mutants
-
ammonium sulfate, DEAE-Toyopearl, CM-Sephadex, Sephadex G-100
-
native enzyme from cucumber cortex, too homogeneity as blue oxidase
-
liquid-liquid extraction in aqueous two-phase systems in continuous process using perforated rotating disc contactor with 10% (w/v) PEG 20000 and 25% (w/v) citrate; pre-purification using a aqueous two-phase system (PEG/citrate)
-
-
Cucurbita pepo condensa
-
-
Cucurbita pepo medullosa
-
ammonium sulfate, DEAE-dextran-silochrome
Cucurbita sp.
-
further purification of different commercial preparations, overview
Cucurbita sp.
-
ammonium sulfate precipitation, DEAE-Sephacel column chromatography, and Sephadex G-100 gel filtration
-
ammonium sulfate fractionation
-
ammonium sulfate fractionation
-
ammonium sulfate, phenyl Sepharose, Sephacryl S-300, Q-Sepharose, preparative isoelectric focusing, basic and acidic enzyme purified from flour, ammonium sulfate, phenyl Sepharose, Q-Sepharose, Mono S, Superdex 200, basic and acidic enzyme purified from immature kernels
-
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
expression of wild-type, Q183R, T527A, E177K, V185K, V188R, P190I, V193P, R194Q, Q382G, H383Y, V385K, R387A, A389N, L539E, H540L, M542L, V543H, W189H, W386H, V193G, V193F, V193H, V193K, V193E, V185K/V188R, V188R/P190I and P190I/V193P mutant enzyme in Aspergillus nidulans
-
co-expression of cytochrome b561 and ascorbate oxidase
-
gene-specific expression studies of the AO gene family in melon reveal that only CmAO1 and CmAO4 are transcriptionally active and differentially regulated dependent on tissue, developmental stage and external stimuli, overview; gene-specific expression studies of the AO gene family in melon reveal that only CmAO1 and CmAO4 are transcriptionally active and differentially regulated dependent on tissue, developmental stage and external stimuli, overview
Q5M5B4, Q5M5B5
cloning of cDNA
-
expressed in Populus tremula x Populus alba
P14133
Nicotiana tabacum L., cv. xanthi over-expressing cucumber ascorbate oxidase. In comparison to wild-type plants, leaves of ascorbate oxidase over-expressing plants exhibit reduced stomatal conductance (due to partial stomatal closure), higher water content, and reduced rates of water loss on detachment. Transgenic plants also exhibit elevated levels of hydrogen peroxide and a decline in hydrogen peroxide-scavenging enzyme activity. Leaf abscisic acid content is also higher in ascorbate oxidase over-expressing plants
-
quantitative expression analysis
-
cloning of cDNA
Cucurbita sp.
-
expression of cDNA in Nicotiana tabacum cell culture
Cucurbita sp.
-
quantitative expression analysis
-
phylogenetic analysis
J7GBJ3
symbiosis-induced AO gene overexpressed in Lotus japonicus during its interaction with either N2-fixing Mesorhizobium loti or the AM fungus Gigaspora margarita, overview
J7GBJ3
overexpression of the enzyme in transgenic tobacco lines
-
expression of RNAi constructs in tomato plants using transfection of WVa106 tomato cotyledons via Agrobacterium strain GV3101, real-time quantitative PCR expression analysis
-
phylogenetic analysis
-
quantitative expression analysis
-
EXPRESSION
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
NaCl-induced ascorbate oxidase activity
-
enzyme expression of Lotus japonicus is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal fungi, symbiosis-induced ascorbate oxidase gene overexpressed in Lotus japonicus during its interaction with either N2-fixing Mesorhizobium loti or the AM fungus Gigaspora margarita, overview
J7GBJ3
ENGINEERING
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
A389N
-
slightly reduced thermostability
E177K
-
slightly reduced thermostability
E540L
-
slightly reduced thermostability
H383Y
-
slightly reduced thermostability
L539E
-
slightly increased thermostability
M542L
-
strongly reduced thermostability
P190I
-
reduced thermostability
P190I/V193P
-
pH optimum shifted to pH 4.5, slightly reduced thermostability
Q183R
-
similar properties as wild-type
Q382G
-
slightly higher thermostability
R194Q
-
similar properties as wild-type
R387A
-
slightly reduced thermostability
T527A
-
similar properties as wild-type
V185K
-
slightly reduced thermostability
V185K/V188R
-
similar properties as wild-type
V188R/P190I
-
no detectable activity
V193E
-
pH optimum shifted to pH 4.5, very thermolabile
V193F
-
slightly reduced thermostability
V193G
-
very thermolabile
V193H
-
slightly reduced thermostability
V193K
-
slightly reduced thermostability
V193P
-
pH optimum shifted to pH 5.0
V193T
-
similar properties as wild-type
V385K
-
reduced thermostability
V543H
-
very thermolabile
W189H
-
no detectable activity
W386H
-
reduced thermostability
additional information
-
mutant with T-DNA inserted into enzyme gene, delay in flowering time, at high salinity, increase in percentage of germination, photosynthetic activity and seed yield
additional information
-
construction of transgenic Nicotiana tabacum plants overexpressing the enzyme in sense orientation, lines P221 and P372, the apoplast ascorbic acid pool is only about 3% reduced in enzyme 'in sense' lines, ascorbic acid oxidase sense leaves exhibit significantly lower dehydroascorbate reductase and ascorbate peroxidase activities than wild-type and antisense leaves, phenotype and effects on enzyme regulation, overview
additional information
-
construction of three transgenic enzyme overexpressing lines R50, R60, and R68, selected on the basis of enzyme expression and single transgene copy number, the overexpression has a slight effect on chlorophyll and carotinoid contents, and on sensitivity to oxidative stress, phenotypes, overview
additional information
-
construction of RNAi knockout plants lacking AAO activity, phenotype, overview. RNAi tomato lines have reduced ascorbate oxidase transcript and activity in leaves. Stomatal conductance is increased in transgenic ascorbate oxidase lines
additional information
Solanum lycopersicum West Virginia 106
-
construction of RNAi knockout plants lacking AAO activity, phenotype, overview. RNAi tomato lines have reduced ascorbate oxidase transcript and activity in leaves. Stomatal conductance is increased in transgenic ascorbate oxidase lines
-
Renatured/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
reconstitution of copper-free apoascorbate oxidase with cuprous copper solution
Cucurbita pepo medullosa
-
refolding after denaturation in urea or guanidinium hydrochloride, enzymatic activity is achieved after a further incubation in anaerobiosis of the refolded enzyme in the presence of cupric ions
Cucurbita pepo medullosa
-
APPLICATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
analysis
-
the enzyme is required in NO measurements to eliminates the interference of ascorbic acid and/or dehydroascorbic acid in the assays, overview
agriculture
P14133
up to 380fold increase in enzyme activity of leaf of transgenic plants, no change in total ascorbate content of apoplast, but redox state of ascorbate is reduced to below the threshold while that of glutathione is increased. Overexpressing plants show substantial increase in foliar injury and greater decline in CO2 assimilation upon exposure to ozone
analysis
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rapid and simple determination of L-ascorbate in food with immobilized enzyme
analysis
Cucurbita sp.
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reagent for analysis of L-ascorbic acid in food
analysis
Cucurbita sp.
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quantitative determination of ascorbic acid with enzyme elctrode containing enzyme immobilized on nylon membrane
medicine
Cucurbita sp.
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reagent for clinical analysis of L-ascorbic acid
agriculture
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expression of enzyme gene in sense and antisense orientation, no significant differences in phenotype except for a delay in flowering time in antisense palnts. At high salinity, increase in percentage of germination, photosynthetic activity and seed yield in antisense plants. Sense plants show a very low redox state of apoplastic ascorbate and increased hydrogen peroxide contents in symplastic and apoplastic spaces
agriculture
Q40588
expression of enzyme in sense- and antisense-orientations, enhanced enzyme activity oxidizes the apoplastic ascorbate pool, decreased enzyme activity increases the amount of ascorbate compared with dehydroascorbate. In sense and antisense plants, enzyme transcript levels are no longer subject to light/dark regulation. Relationship between enzyme activity and plant height and biomass