IUBMB Enzyme Nomenclature

EC 1.23.5.1

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

For diagram of reaction click here.

Glossary: violaxanthin = (3S,3'S,5R,5'R,6S,6'S)-5,6:5',6'-diepoxy-5,5',6,6'-tetrahydro-β,β-carotene-3,3'-diol
antheraxanthin = (3R,3'S,5'R,6'S)-5',6'-epoxy-5',6'-dihydro-β,β-carotene-3,3'-diol
zeaxanthin = (3R,3'R)-β,β-carotene-3,3'-diol

Other name(s): VDE

Systematic name: violaxanthin:ascorbate oxidoreductase

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.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:

References:

1. Yamamoto, H.Y. and Higashi, R.M. Violaxanthin de-epoxidase. Lipid composition and substrate specificity. Arch. Biochem. Biophys. 190 (1978) 514-522. [PMID: 102251]

2. Rockholm, D.C. and Yamamoto, H.Y. Violaxanthin de-epoxidase. Plant Physiol. 110 (1996) 697-703. [PMID: 8742341]

3. Bugos, R.C., Hieber, A.D. and Yamamoto, H.Y. Xanthophyll cycle enzymes are members of the lipocalin family, the first identified from plants. J. Biol. Chem. 273 (1998) 15321-15324. [PMID: 9624110]

4. Kuwabara, T., Hasegawa, M., Kawano, M. and Takaichi, S. Characterization of violaxanthin de-epoxidase purified in the presence of Tween 20: effects of dithiothreitol and pepstatin A. Plant Cell Physiol. 40 (1999) 1119-1126. [PMID: 10635115]

5. Latowski, D., Kruk, J., Burda, K., Skrzynecka-Jaskierm, M., Kostecka-Gugala, A. and Strzalka, K. Kinetics of violaxanthin de-epoxidation by violaxanthin de-epoxidase, a xanthophyll cycle enzyme, is regulated by membrane fluidity in model lipid bilayers. Eur. J. Biochem. 269 (2002) 4656-4665. [PMID: 12230579]

6. Goss, R. Substrate specificity of the violaxanthin de-epoxidase of the primitive green alga Mantoniella squamata (Prasinophyceae). Planta 217 (2003) 801-812. [PMID: 12748855]

7. Latowski, D., Akerlund, H.E. and Strzalka, K. Violaxanthin de-epoxidase, the xanthophyll cycle enzyme, requires lipid inverted hexagonal structures for its activity. Biochemistry 43 (2004) 4417-4420. [PMID: 15078086]

[EC 1.23.5.1 created 2005 as EC 1.10.99.3, transfered 2015 to EC 1.23.5.1]


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