The Enzyme Database

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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 the xanthophyll cycle, 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: 57534-73-3
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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