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ENZYME entry: EC

Accepted Name
Violaxanthin de-epoxidase.
Alternative Name(s)
Reaction catalysed
Violaxanthin + 2 L-ascorbate <=> antheraxanthin + 2 L-dehydroascorbate + H(2)O
  • Along with EC, 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.
  • Formerly EC
PRIAM enzyme-specific profiles1.23.5.1
KEGG Ligand Database for Enzyme Nomenclature1.23.5.1
IUBMB Enzyme Nomenclature1.23.5.1
MEDLINEFind literature relating to
Rhea expert-curated reactions1.23.5.1
Q39249, VDE_ARATH;  Q40251, VDE_LACSA;  Q9SM43, VDE_SPIOL;  
Q40593, VDE_TOBAC;  

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