Zeaxanthin epoxidase

Zeaxanthin epoxidase (EC 1.14.13.90, Zea-epoxidase) is an enzyme with systematic name zeaxanthin,NAD(P)H:oxygen oxidoreductase. This enzyme catalyses the following chemical reaction

zeaxanthin + 2 NAD(P)H + 2 H⁺ + 2 O₂ ⇌ violaxanthin + 2 NAD(P)⁺ + 2 H₂O (overall reaction) (1a) zeaxanthin + NAD(P)H + H⁺ + O₂ ⇌ antheraxanthin + NAD(P)⁺ + H₂O (1b) antheraxanthin + NAD(P)H + H⁺ + O₂ ⇌ violaxanthin + NAD(P)⁺ + H₂O

Zeaxanthin epoxidase is a flavoprotein (FAD) that is active under conditions of low light.