ExplorEnz: EC 1.14.15.21

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1.14.15.21

Accepted name:

zeaxanthin epoxidase

Reaction:

zeaxanthin + 4 reduced ferredoxin [iron-sulfur] cluster + 4 H⁺ + 2 O₂ = violaxanthin + 4 oxidized ferredoxin [iron-sulfur] cluster + 2 H₂O (overall reaction)
(1a) zeaxanthin + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = antheraxanthin + 2 oxidized ferredoxin [iron-sulfur] cluster + H₂O
(1b) antheraxanthin + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = violaxanthin + 2 oxidized ferredoxin [iron-sulfur] cluster + H₂O

For diagram of the xanthophyll cycle, click here

Other name(s):

Zea-epoxidase

Systematic name:

zeaxanthin,reduced ferredoxin:oxygen oxidoreductase

Comments:

A flavoprotein (FAD) that is active under conditions of low light. Along with EC 1.23.5.1, violaxanthin de-epoxidase, this enzyme forms part of the xanthophyll (or violaxanthin) cycle, which is involved in protecting the plant against damage by excess light. It will also epoxidize lutein in some higher-plant species.

Links to other databases:

BRENDA, EXPASY, Gene, KEGG, MetaCyc, CAS registry number: 149718-34-3

References:

1.	Buch, K., Stransky, H. and Hager, A. FAD is a further essential cofactor of the NAD(P)H and O₂-dependent zeaxanthin-epoxidase. FEBS Lett. 376 (1995) 45–48. [DOI] [PMID: 8521963]
2.	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. [DOI] [PMID: 9624110]
3.	Thompson, A.J., Jackson, A.C., Parker, R.A., Morpeth, D.R., Burbidge, A. and Taylor, I.B. Abscisic acid biosynthesis in tomato: regulation of zeaxanthin epoxidase and 9-cis-epoxycarotenoid dioxygenase mRNAs by light/dark cycles, water stress and abscisic acid. Plant Mol. Biol. 42 (2000) 833–845. [PMID: 10890531]
4.	Hieber, A.D., Bugos, R.C. and Yamamoto, H.Y. Plant lipocalins: violaxanthin de-epoxidase and zeaxanthin epoxidase. Biochim. Biophys. Acta 1482 (2000) 84–91. [DOI] [PMID: 11058750]
5.	Frommolt, R., Goss, R. and Wilhelm, C. The de-epoxidase and epoxidase reactions of Mantoniella squamata (Prasinophyceae) exhibit different substrate-specific reaction kinetics compared to spinach. Planta 213 (2001) 446–456. [PMID: 11506368]
6.	Frommolt, R., Goss, R. and Wilhelm, C. Erratum Report. The de-epoxidase and epoxidase reactions of Mantoniella squamata (Prasinophyceae) exhibit different substrate-specific reaction kinetics compared to spinach. Planta 213 (2001) 492.
7.	Matsubara, S., Morosinotto, T., Bassi, R., Christian, A.L., Fischer-Schliebs, E., Luttge, U., Orthen, B., Franco, A.C., Scarano, F.R., Forster, B., Pogson, B.J. and Osmond, C.B. Occurrence of the lutein-epoxide cycle in mistletoes of the Loranthaceae and Viscaceae. Planta 217 (2003) 868–879. [DOI] [PMID: 12844265]

[EC 1.14.15.21 created 2005 as EC 1.14.13.90, transferred 2016 to EC 1.14.15.21]