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Information on EC 1.8.5.1 - glutathione dehydrogenase (ascorbate) and Organism(s) Cenchrus americanus and UniProt Accession U5XYA0

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This record set is specific for:
Cenchrus americanus
UNIPROT: U5XYA0 not found.
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The taxonomic range for the selected organisms is: Cenchrus americanus
The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
Synonyms
mt-ii, dehydroascorbate reductase, dhar, metallothionein-1, gsto1-1, dioscorin, metallothionein-2, dha reductase, dhar1, dhar2, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dehydroascorbate reductase
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DasA reductase
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dehydroascorbate reductase
dehydroascorbic acid reductase
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dehydroascorbic reductase
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dehydrogenase, glutathione (ascorbate)
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DHA reductase
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DHA-R
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-
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GDOR
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glutathione dehydroascorbate reductase
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glutathione-dependent dehydroascorate reductase
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glutathione:dehydroascorbic acid oxidoreductase
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GSH-DHAR
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GSH:DHA-oxidoreductase
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-
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
2 glutathione + dehydroascorbate = glutathione disulfide + ascorbate
show the reaction diagram
the reaction of DHAR proceeds by a bi-uni-uni-uniping-pong enzymatic mechanism. In step 1, the DHA molecule is bound to the catalytic cysteine residue of the reduced form of DHAR (DHAR-S-) and is reduced to ascorbate. This reduction involves nucleophilic attack by the catalytic cysteine residue and the formation of cysteine sulfenic acid (sulfenylated DHAR, DHAR-SOH). In step 2, the reactive sulfenic acid at the catalytic cysteine residue reacts with GSH bound at the G-site and generates the mixed disulfide (DHAR-S-SG). Subsequently, the second GSH molecule binds to the H-site and may be deprotonated to GS-. Then, the GSH bound with the catalytic cysteine residue is removed by the nucleophilic attack of GS- at the H-site. As a result, a catalytic cysteine residue is reduced and one molecule of glutathione disulfide (GSSG) is released (step 3). Unlike most other GSTs, DHARs have an active-site cysteine in place of serine, and rather than stabilizing the thiolate anion of GSH (GS-), this change confers the capacity for reversible disulfide bond formation with GSH as part of the catalytic mechanism
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
redox reaction
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oxidation
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reduction
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PATHWAY SOURCE
PATHWAYS
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-, -
SYSTEMATIC NAME
IUBMB Comments
glutathione:dehydroascorbate oxidoreductase
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CAS REGISTRY NUMBER
COMMENTARY hide
9026-38-4
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SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2 glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
-
?
glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
-
?
glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
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?
additional information
?
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while the reduction of dehydroascorbate (DHA) to ascorbate can occur chemically at significant rates, DHAR is able to accelerate the reaction, in both cases reduced glutathione (GSH) is used as the reductant
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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
2 glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
-
?
glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
-
?
glutathione + dehydroascorbate
glutathione disulfide + ascorbate
show the reaction diagram
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-
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-
?
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.13 - 0.1334
dehydroascorbate
0.04 - 0.04167
glutathione
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.5 - 8
more than 50% activity between pH 6.5 and 8.0
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
30 - 50
more than 80% activity between 30 and 50°C
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6
calculated from amino acid sequence
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
additional information
isozymes can occur in chloroplast, mitochondrion, cytosol, and peroxisome. DHA generated in cellular compartments lacking DHAR may be transported to the cytosol for re-reduction through plasma membrane carriers
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Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
DHA reductase (DHAR) belongs to the glutathione S-transferase (GST) superfamily. Unlike most other GSTs, DHARs have an active-site cysteine in place of serine, and rather than stabilizing the thiolate anion of GSH (GS-), this change confers the capacity for reversible disulfide bond formation with GSH as part of the catalytic mechanism
malfunction
site-directed mutagenesis of the catalytic cysteine abolishes DHAR activity
metabolism
the ascorbate-glutathione pathway is recognized to be a key player in H2O2 metabolism, in which reduced glutathione (GSH) regenerates ascorbate by reducing dehydroascorbate (DHA), either chemically or via DHA reductase (DHAR). Importance of DHAR in coupling the ascorbate and glutathione pools with H2O2 metabolism, together with its functions in plant defense, growth, and development. The ascorbate-glutathione (or Foyer-Halliwell-Asada) pathway plays a central role in H2O2 detoxification in plants and operates in the cytosol, chloroplasts, mitochondria and peroxisomes. Although GSH oxidation is potentially mediated by some glutathione-transferases (GSTs) and peroxiredoxins (PRXs), DHAR is identified as being a key player in ensuring GSH oxidation during oxidative stress
physiological function
additional information
three-dimensional structure analysis of isozyme PgDHAR1. DHARs have a monomeric state that is unlike most GSTs
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
U5XYA0_CENAM
213
0
23415
TrEMBL
other Location (Reliability: 5)
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
monomer
DHARs have a monomeric state that is unlike most GSTs. The enzyme consists of two domains. The N-terminal domain contains residues responsible for GSH binding (the G-site), which is structurally similar to, and has evolved from, the thioredoxin fold, whilst the C-terminal alpha-helical domain provides the majority of the binding site for the hydrophobic substrate (the H-site)
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
isozyme PgDHAR1, X-ray diffraction structure determination and analysis
in complex with acetate or glycerol
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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
site-directed mutagenesis of the catalytic cysteine abolishes DHAR activity
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
Ni-NTA column chromatography
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expressed in Escherichia coli Rossetta pLysS cells
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
the enzyme expression is down-regulated under salinity stress (250 mM NaCl)
the enzyme expression is up-regulated in response to high temperature (45°C)
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Krishna Das, B.; Kumar, A.; Maindola, P.; Mahanty, S.; Jain, S.K.; Reddy, M.K.; Arockiasamy, A.
Non-native ligands define the active site of Pennisetum glaucum (L.) R. Br dehydroascorbate reductase
Biochem. Biophys. Res. Commun.
473
1152-1157
2016
Cenchrus americanus
Manually annotated by BRENDA team
Pandey, P.; Achary, V.M.; Kalasamudramu, V.; Mahanty, S.; Reddy, G.M.; Reddy, M.K.
Molecular and biochemical characterization of dehydroascorbate reductase from a stress adapted C4 plant, pearl millet [Pennisetum glaucum (L.) R. Br]
Plant Cell Rep.
33
435-445
2014
Cenchrus americanus (U5XYA0), Cenchrus americanus
Manually annotated by BRENDA team
Ding, H.; Wang, B.; Han, Y.; Li, S.
The pivotal function of dehydroascorbate reductase in glutathione homeostasis in plants
J. Exp. Bot.
71
3405-3416
2020
Acer saccharinum, Actinidia chinensis, Avena sativa, Brassica napus, Hordeum vulgare, Pisum sativum, Populus trichocarpa, Populus trichocarpa (D2WL73), Populus trichocarpa (D2WL74), Populus trichocarpa (D2WL75), Liriodendron chinense (A0A6C0W973), Pinus bungeana (B2ZHM6), Zea mays (C0P9V2), Ipomoea batatas (D2CGD4), Populus tomentosa (J9WN12), Populus tomentosa (J9WNR5), Populus tomentosa (J9WQY6), Solanum tuberosum (M1BA41), Oryza sativa Japonica Group (Q65XA0), Arabidopsis thaliana (Q8LE52), Arabidopsis thaliana (Q9FRL8), Arabidopsis thaliana (Q9FWR4), Spinacia oleracea (Q9T2H6), Cenchrus americanus (U5XYA0), Arabidopsis thaliana Col-0 (Q9FWR4)
Manually annotated by BRENDA team