Crystallographic study of glutathione-dependent dehydroascorbate reductase from spinach chloroplasts

摘要

Ascorbate is the vital compound in both animal and plant cells. It functions as an electron donor in a variety of physiological processes. For example, ascorbate influences on many enzyme activities as a cofactor often by keeping metal ions associated with such enzymes in the reduced form. Ascorbate also reduces and scavenges many types of active oxygen species directly or enzymatically through peroxidase. Two-electron oxidation of ascorbate produces dehydroascorbate (DHA). Because DHA spontaneouslydecays through hydration, the net loss of ascorbate is anticipated in the absence of a mechanism to maintain high concentrations of ascorbate in the cell. This could be accomplished either through a direct chemical reduction of DHA by reduced glutathione (GSH) or through an enzymatic reduction (Rose & Bode, 1992).