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Information on EC 1.11.1.11 - L-ascorbate peroxidase and Organism(s) Populus tomentosa and UniProt Accession Q5S1V5

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EC Tree
     1 Oxidoreductases
         1.11 Acting on a peroxide as acceptor
             1.11.1 Peroxidases
                1.11.1.11 L-ascorbate peroxidase
IUBMB Comments
A heme protein. Oxidizes ascorbate and low molecular weight aromatic substrates. The monodehydroascorbate radical produced is either directly reduced back to ascorbate by EC 1.6.5.4 [monodehydroascorbate reductase (NADH)] or undergoes non-enzymic disproportionation to ascorbate and dehydroascorbate.
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This record set is specific for:
Populus tomentosa
UNIPROT: Q5S1V5
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The taxonomic range for the selected organisms is: Populus tomentosa
The enzyme appears in selected viruses and cellular organisms
Reaction Schemes
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2
L-ascorbate
+
H2O2
+
2
H+
=
L-ascorbate
+
L-dehydroascorbate
+
2
H2O
2
+
+
2
=
+
+
2
Synonyms
ascorbate peroxidase, apex2, cytosolic ascorbate peroxidase, lmapx, ascorbate peroxidase 2, l-ascorbate peroxidase, ascorbate peroxidase 1, ascorbic acid peroxidase, osapx8, osapx2, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
peroxisomal ascorbate peroxidase
-
ascorbate peroxidase
-
-
-
-
ascorbic acid peroxidase
-
-
-
-
L-ascorbic acid peroxidase
-
-
-
-
L-ascorbic acid-specific peroxidase
-
-
-
-
peroxidase, ascorbate
-
-
-
-
thylakoid ascorbate peroxidase
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
redox reaction
-
-
-
-
oxidation
-
-
-
-
reduction
-
-
-
-
peroxidation
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
L-ascorbate:hydrogen-peroxide oxidoreductase
A heme protein. Oxidizes ascorbate and low molecular weight aromatic substrates. The monodehydroascorbate radical produced is either directly reduced back to ascorbate by EC 1.6.5.4 [monodehydroascorbate reductase (NADH)] or undergoes non-enzymic disproportionation to ascorbate and dehydroascorbate.
CAS REGISTRY NUMBER
COMMENTARY hide
72906-87-7
-
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
L-ascorbate + H2O2
dehydroascorbate + H2O
show the reaction diagram
-
-
-
?
2 L-ascorbate + H2O2 + 2 H+
L-ascorbate + L-dehydroascorbate + 2 H2O
show the reaction diagram
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
L-ascorbate + H2O2
dehydroascorbate + H2O
show the reaction diagram
-
-
-
?
2 L-ascorbate + H2O2 + 2 H+
L-ascorbate + L-dehydroascorbate + 2 H2O
show the reaction diagram
-
-
-
-
?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Fe2+
-
in the heme group
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.12
H2O2
25°C
0.53
L-ascorbate
25°C
3.43
H2O2
pH 7.0, temperature not specified in the publication
0.5
L-ascorbate
pH 7.0, temperature not specified in the publication
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2.03
H2O2
25°C
1.74
L-ascorbate
25°C
29.7
H2O2
pH 7.0, temperature not specified in the publication
49.6
L-ascorbate
pH 7.0, temperature not specified in the publication
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
59.5
H2O2
pH 7.0, temperature not specified in the publication
14.5
L-ascorbate
pH 7.0, temperature not specified in the publication
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.8
activity assay
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5 - 9
pH 5.0: 68% of maximal activity, pH 9.0: 23% of maximal activity
4
80% of maximum activity
7
25% of maximum activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
20 - 55
20°C: about 65% of maximal activity, 55°C: about 40% of maximal activity
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
SwissProt
Manually annotated by BRENDA team
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
expression levels are higher in leaves than in roots or stems
Manually annotated by BRENDA team
expression levels are higher in leaves than in roots or stems
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
additional information
-
transcriptome analysis during light-induced chloroplast development, detailed overview
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
-
light-induced chloroplast development is enhanced in PtotAPX-overexpressing transgenic Populus tomentosa callus with lower levels of hydrogen peroxide, but is suppressed in PtotAPX antisense transgenic callus with higher levels of hydrogen peroxide
metabolism
-
chloroplasts with elaborate thylakoids can develop from proplastids in the cells of calli derived from leaf tissues of Populus tomentosa upon exposure to light. Chloroplast development is confirmed at the molecular and cellular levels and transcriptome analysis reveals that genes related to photoreceptors and photosynthesis are significantly upregulated during chloroplast development in a time-dependent manner. In light-induced chloroplast development, a key process is the removal of hydrogen peroxide, in which thylakoid-localized PtotAPX plays a major role
physiological function
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
Q5S1V5_POPTO
286
1
31591
TrEMBL
other Location (Reliability: 3)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
31580
2 * 31580, calculated from sequence
37370
2 * 37370, SDS-PAGE
74000
gel filtration
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dimer
?
x * 33240, calculated, x * 33000, SDS-PAGE
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
overexpression or suppression of PtoAPX in Populus tomentosa callus. Light-induced chloroplast development is enhanced in PtotAPX-overexpressing transgenic Populus tomentosa callus with lower levels of hydrogen peroxide, but is suppressed in PtotAPX antisense transgenic callus with higher levels of hydrogen peroxide. The suppression of light-induced chloroplast development in PtotAPX antisense transgenic callus is relieved by the exogenous reactive oxygen species scavenging agent N,N'-dimethylthiourea (DMTU)
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
into the pBI121 binary vector for a Agrobacterium tumefaciens-mediated tobacco leaf disc transformation, a CaMV 35S promoter and a rd29A promoter driven construct is used
enzyme PtotAPX expression analysis in callus cultures, recombinant expression of GFP-tagged enzyme in tobacco plants, localization to the chloroplasts
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
APX activity in the 35S-PpAPX transgenic lines increases by 50% compared to the activity in the control lines, activity is 80% higher in the leaves in response to drought or salt stresses, the PpAPX transcript level is very low under normal growing conditions in rd29Ap-PpAPX plants, but clearly increased under drought stress
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
agriculture
the transgenic plants show enhanced tolerance to oxidative stress, salt and drought, PpAPX does not play a significant role under normal growing conditions, but do ameliorate oxidative injury under abiotic stress, the Ad29 promoter shoul be used as an inducible promoter in transgenic works
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Lu, H.; Han, R.L.; Jiang, X.N.
Heterologous expression and characterization of a proxidomal ascorbate peroxidase from Populus tomentosa
Mol. Biol. Rep.
36
21-27
2007
Populus tomentosa (Q5S1V5), Populus tomentosa
Manually annotated by BRENDA team
Li, Y.; Hai, R.; Du, X.; Jiang, X.; Lu, H.
Over-expression of a Populus peroxisomal ascorbate peroxidase (PpAPX) gene in tobacco plants enhances stress tolerance
Plant Breed.
128
404-410
2009
Populus tomentosa (Q5S1V5)
Manually annotated by BRENDA team
Cao, S.; Du, X.; Li, L.; Liu, Y.; Zhang, L.; Pan, X.; Li, Y.; Li, H.; Lu, H.
Overexpression of Populus tomentosa cytosolic ascorbate peroxidase enhances abiotic stress tolerance in tobacco plants
Russ. J. Plant Physiol.
64
224-234
2017
Populus tomentosa (U5RZT9)
-
Manually annotated by BRENDA team
Li, C.; Liu, Y.; Liu, X.; Mai, K.K.K.; Li, J.; Guo, X.; Zhang, C.; Li, H.; Kang, B.H.; Hwang, I.; Lu, H.
Chloroplast thylakoid ascorbate peroxidase PtotAPX plays a key role in chloroplast development by decreasing hydrogen peroxide in Populus tomentosa
J. Exp. Bot.
72
4333-4354
2021
Populus tomentosa
Manually annotated by BRENDA team