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Information on EC 1.23.5.1 - violaxanthin de-epoxidase

for references in articles please use BRENDA:EC1.23.5.1

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IUBMB Comments

Along with EC 1.14.15.21, 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.

The enzyme appears in viruses and cellular organisms

Synonyms
violaxanthin de-epoxidase, csvde, vx de-epoxidase, zmvde1, ahvde, more

REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
antheraxanthin + L-ascorbate = zeaxanthin + L-dehydroascorbate + H2O
show the reaction diagram
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violaxanthin + 2 L-ascorbate = zeaxanthin + 2 L-dehydroascorbate + 2 H2O
show the reaction diagram
overall reaction
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violaxanthin + L-ascorbate = antheraxanthin + L-dehydroascorbate + H2O
show the reaction diagram