Tags: Enzyme.
L-gulonolactone oxidase (EC 1.1.3.8) is an enzyme that produces vitamin C but is non-functional in humans and some other primates. It catalyzes the reaction of D-glucuronolactone (also known as L-gulono-14-lactone) with oxygen to L-xylo-hex-3-gulonolactone and hydrogen peroxide. It uses FAD as a cofactor. The L-xylo-hex-3-gulonolactone (2-keto-gulono-gamma-lactone) is able to convert to hexuronic acid (ascorbic acid) spontaneously without enzymatic action.