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ENZYME

ENZYME entry: EC 1.23.5.1

Accepted Name
violaxanthin de-epoxidase
Alternative Name(s)
VDE
Reaction catalysed
all-trans-violaxanthin + 2 L-ascorbate <=> all-trans-zeaxanthin + 2 H2O + 2 L-dehydroascorbate
Comment(s)
  • Along with EC 1.14.15.21, 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 1.10.99.3.
Cross-references
BRENDA1.23.5.1
EC2PDB1.23.5.1
ExplorEnz1.23.5.1
PRIAM enzyme-specific profiles1.23.5.1
KEGG Ligand Database for Enzyme Nomenclature1.23.5.1
IUBMB Enzyme Nomenclature1.23.5.1
IntEnz1.23.5.1
MEDLINEFind literature relating to 1.23.5.1
MetaCyc1.23.5.1
Rhea expert-curated reactions1.23.5.1
UniProtKB/Swiss-Prot
Q39249, VDE_ARATHQ40251, VDE_LACSAQ9SM43, VDE_SPIOL
Q40593, VDE_TOBAC

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