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EC 1.10.99.3 Details

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EC number

1.10.99.3

Accepted name

violaxanthin de-epoxidase

Reaction

violaxanthin + 2 L-ascorbate = zeaxanthin + 2 L-dehydroascorbate + 2 H₂O (overall reaction);;(1a) violaxanthin + L-ascorbate = antheraxanthin + L-dehydroascorbate + H₂O;;(1b) antheraxanthin + L-ascorbate = zeaxanthin + L-dehydroascorbate + H₂O

Other name(s)

VDE

Systematic name

violaxanthin:ascorbate oxidoreductase

CAS registry number

57534-73-3

Comment

Along with EC 1.14.13.90, zeaxanthin epoxidase, this enzyme forms part of the xanthophyll (or violaxanthin) cycle for controlling the concentration of zeaxanthin in chloroplasts. It is activated by a low pH of the thylakoid lumen (produced by high light intensity). Zeaxanthin induces the dissipation of excitation energy in the chlorophyll of the light-harvesting protein complex of photosystem II. In higher plants the enzyme reacts with all-trans-diepoxides, such as violaxanthin, and all-trans-monoepoxides, but in the alga Mantoniella squamata, only the diepoxides are good substrates.

History

created 2005, deleted 2014

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.4 Acting on the CH-NH₂ group of donors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.8.1 With NAD⁺ or NADP⁺ as acceptor

1.8.2 With a cytochrome as acceptor

1.8.3 With oxygen as acceptor

1.8.4 With a disulfide as acceptor

1.8.5 With a quinone or similar compound as acceptor

1.8.6 With a nitrogenous group as acceptor (deleted sub-subclass)

1.8.7 With an iron-sulfur protein as acceptor

1.8.98 With other, known, physiological acceptors

1.8.99 With unknown physiological acceptors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.11 Acting on a peroxide as acceptor

1.11.1 Peroxidases

1.11.1.1 NADH peroxidase

1.11.1.2 NADPH peroxidase

1.11.1.3 fatty-acid peroxidase

1.11.1.4 created 1961, deleted 1964, reinstated 1965 as EC 1.13.1.12, deleted 1972

1.11.1.5 cytochrome-c peroxidase

1.11.1.6 catalase

1.11.1.7 peroxidase

1.11.1.8 iodide peroxidase

1.11.1.9 glutathione peroxidase

1.11.1.10 chloride peroxidase

1.11.1.11 L-ascorbate peroxidase

1.11.1.12 phospholipid-hydroperoxide glutathione peroxidase

1.11.1.13 manganese peroxidase

1.11.1.14 lignin peroxidase

1.11.1.15 peroxiredoxin

1.11.1.16 versatile peroxidase

1.11.1.17 glutathione amide-dependent peroxidase

1.11.1.18 bromide peroxidase

1.11.1.19 dye decolorizing peroxidase

1.11.1.20 prostamide/prostaglandin F_2α synthase

1.11.1.21 catalase-peroxidase

1.11.1.22 hydroperoxy fatty acid reductase

1.11.1.23 (S)-2-hydroxypropylphosphonic acid epoxidase

1.11.1.24 thioredoxin-dependent peroxiredoxin

1.11.1.25 glutaredoxin-dependent peroxiredoxin

1.11.1.26 NADH-dependent peroxiredoxin

1.11.1.27 glutathione-dependent peroxiredoxin

1.11.1.28 lipoyl-dependent peroxiredoxin

1.11.1.29 mycoredoxin-dependent peroxiredoxin

1.11.2 Peroxygenases

1.12 Acting on hydrogen as donor

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.16.1 With NAD⁺ or NADP⁺ as acceptor

1.16.3 With oxygen as acceptor

1.16.5 With a quinone or similar compound as acceptor

1.16.8 With a flavin as acceptor

1.16.9 With a copper protein as acceptor

1.16.98 With other, known, physiological acceptors

1.16.99 With unknown physiological acceptors

1.17 Acting on CH or CH₂ groups

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.22 Acting on halogen in donors

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)