ID   1.10.99.3
DE   Violaxanthin de-epoxidase.
AN   VDE.
CA   (1) Violaxanthin + ascorbate = antheraxanthin + dehydroascorbate + H(2)O.
CA   (2) Antheraxanthin + ascorbate = zeaxanthin + dehydroascorbate + H(2)O.
CC   -!- Along with EC 1.14.13.90, this enzyme forms part of the xanthophyll
CC       (or violaxanthin) cycle for controlling the concentration of
CC       zeaxanthin in chloroplasts.
CC   -!- It is activated by a low pH of the thylakoid lumen (produced by high
CC       light intensity).
CC   -!- Zeaxanthin induces the dissipation of excitation energy in the
CC       chlorophyll of the light-harvesting protein complex of photosystem
CC       II.
CC   -!- In higher plants the enzyme reacts with all-trans-diepoxides, such as
CC       violaxanthin, and all-trans-monoepoxides, but in the alga Mantoniella
CC       squamata, only the diepoxides are good substrates.
DR   Q39249, VDE_ARATH  ;  Q40251, VDE_LACSA  ;  Q9SM43, VDE_SPIOL  ;
DR   Q40593, VDE_TOBAC  ;
//