Eric E. Conn

The Enzymatic Oxidation and Reduction of Glutathione

Publisher Summary This chapter discusses the enzymatic oxidation and reduction of glutathione (GSH). The ability of living tissues to reduce added GSSG and to keep tissue glutathione in the reduced form is undoubtedly largely because of glutathione reductase and TPN-reducing systems of the tissues. The ability of animal tissues to reduce dehydroascorbic acid and to keep it reduced is attributed to the nonenzymatic reducing capacity of GSH. A physiological relationship between glutathione and ascorbic acid is indicated by the observed parallel changes in the GSH and vitamin C content of sprouting potatoes and of the adrenal gland. The effect of glutathione on the enzyme activity of proteins containing sensitive sulfhydryl groups is well known. Ascorbic-acid oxidase appears to be characteristically a plant enzyme. Phenol oxidases and peroxidase systems are also found in many higher plants. Such enzymes can cause oxidation of ascorbate indirectly by virtue of the nonenzymatic oxidation of ascorbic acid by compounds of quinoid structure formed from the phenolic substrate.