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Information on EC 1.11.1.11 - L-ascorbate peroxidase and Organism(s) Gossypium hirsutum and UniProt Accession Q39780

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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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Gossypium hirsutum
UNIPROT: Q39780
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The taxonomic range for the selected organisms is: Gossypium hirsutum
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
ascorbate peroxidase
-
glyoxysomal APX
-
ascorbate peroxidase
ascorbate peroxidase 1
-
ascorbate peroxidase 2
-
ascorbic acid peroxidase
-
-
-
-
cytosolic ascorbate peroxidase
-
-
GhAPX1
L-ascorbic acid peroxidase
-
-
-
-
L-ascorbic acid-specific peroxidase
-
-
-
-
peroxidase, ascorbate
-
-
-
-
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
-
-
-
-
?
GSSG + H2O2
?
show the reaction diagram
about 20% of the activity with L-ascorbate
-
-
?
guaiacol + H2O2
?
show the reaction diagram
about 30% of the activity with L-ascorbate
-
-
?
L-ascorbate + H2O2
dehydroascorbate + H2O
show the reaction diagram
additional information
?
-
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
-
-
-
-
?
L-ascorbate + H2O2
dehydroascorbate + H2O
show the reaction diagram
-
-
-
?
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.43
L-ascorbate
-
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
260
L-ascorbate
-
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.5
oxidation of ascorbate
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5 - 7.5
pH 5: about 50% of maximal activity, pH 7.5: about 50% of maximal activity
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
UniProt
Manually annotated by BRENDA team
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
-
downregulation of cytosolic ascorbate peroxidases inhibits the development of sink organs in cotton. Downregulated expression of cAPXs inhibits the development of cotton bolls, fibers, and seeds and reduces the storage capacity of the sink organs. The photosynthetic rate is suppressed in the knockout mutant plants, and the reactive oxygen species level is increased in guard cells. Overexpression of GhAPX1 has little effect on the photosynthetic characteristics of the plants. The decrease of cAPX expression in leaves increases ROS level in stomatal guard cells, leading to the decrease of stomatal aperture, which might decrease the supply of carbon dioxide and water used for photosynthesis. The downregulation of cytosolic ascorbate peroxidases (APXs) decreases the water content and increases the water loss rate in cotton leaf. There is a close relationship between the stomatal opening and the inhibition of plant growth caused by the deficiency of antioxidant enzyme in cells
physiological function
-
cytosolic ascorbate peroxidases (APXs) are hydrogen peroxide (H2O2) scavenging enzymes in plants. H2O2 is a signaling molecule involved in regulating photosynthesis in plants. Cytosolic ascorbate peroxidase members provide an important guarantee to maintain photosynthetic rate
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
Q39780_GOSHI
288
1
31942
TrEMBL
other Location (Reliability: 2)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
28000
2 * 28000, calculated from sequence
31500
2 * 31500, His-tag fused enzyme, SDS-PAGE
64200
gel filtration
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dimer
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
generation of transgenic cotton with changes of endogenous ROS by overexpressing or suppressing the expression of cytosolic ascorbate peroxidases (APXs). Downregulation of cytosolic ascorbate peroxidases inhibits the development of sink organs in Gossipium hirsutum. Plant growth and plant size, including plant heights and leaf sizes (lengths and widths), are seriously reduced in the cAPX-suppressed cottons compared to wild-type plants, phenotypes, detailed overview. Downregulated expression of cAPXs inhibits the development of cotton bolls, fibers, and seeds and reduces the storage capacity of the sink organs. The photosynthetic rate is suppressed in the mutant plants. Overexpression of GhAPX1 has little effect on the photosynthetic characteristics of the plants, except that the transpiration rate (Trmmol) and leaf surface temperature (CTleaf) are lower than in the control plant. The downregulation of cytosolic ascorbate peroxidases (APXs) decreases the water content and increases the water loss rate in cotton leaf
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
GhAPX1 is expressed in Escherichia coli
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
transcript level and the total APX activity are highly induced in response to in vitro applied H2O2 or ethylene, up-regulated during fiber cell elongating
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Li, H.B.; Qin, Y.M.; Pang, Y.; Song, W.Q.; Mei, W.Q.; Zhu, Y.X.
A cotton ascorbate peroxidase is involved in hydrogen peroxide homeostasis during fibre cell development
New Phytol.
175
462-471
2007
Gossypium hirsutum (A7KIX5), Gossypium hirsutum
Manually annotated by BRENDA team
Qin, Y.M.; Hu, C.Y.; Zhu, Y.X.
The ascorbate peroxidase regulated by H(2)O(2) and ethylene is involved in cotton fiber cell elongation by modulating ROS homeostasis
Plant Signal. Behav.
3
194-196
2008
Gossypium hirsutum (A7KIX5), Gossypium hirsutum (C6ZDA9), Gossypium hirsutum (C6ZDB0), Gossypium hirsutum (Q39780), Gossypium hirsutum
Manually annotated by BRENDA team
Guo, K.; Li, Z.; Tian, H.; Du, X.; Liu, Z.; Huang, H.; Wang, P.; Ye, Z.; Zhang, X.; Tu, L.
Cytosolic ascorbate peroxidases plays a critical role in photosynthesis by modulating reactive oxygen species level in stomatal guard cell
Front. Plant Sci.
11
0000
2020
Gossypium hirsutum
Manually annotated by BRENDA team