Glutathione protein disulfide oxidoreductase

Protein-disulfide reductase (glutathione) [ glutathione protein-disulfide oxidoreductase EC 1.8.4.2) has been reported in hepatic tissue (52). The enzyme rapidly cleaved the three disulfide bonds of insulin and the disulfide bonds of other proteins. The Km for reduced glutathione was 8.9 X 10 3M, a very high value. The enzyme catalyzed the reaction (Equation 3) from either direction. 

In addition to If PDO and other protein disulfide oxidoreductases, the thioredoxin fold has also been found in other proteins, including glutathione... 

In neural cells, the redox status is controlled by the thioredoxin (Trx) and glutathione (GSH) systems that scavenge harmful intracellular ROS. Thioredoxins are antioxidants that serve as a general protein disulphide oxidoreductase (Saitoh et al., 1998). They interact with a broad range of proteins by a redox mechanism based on the reversible oxidation of 2 cysteine thiol groups to a disulphide, accompanied by the transfer of 2 electrons and 2 protons. These proteins maintain their reduced state through the thioredoxin system, which consists of NADPH, thioredoxin reductase (TR), and thioredoxin (Trx) (Williams, Jr. et al., 2000 Saitoh et al., 1998). The thioredoxin system is a system inducible by oxidative stress that reduces the disulfide bond in proteins (Fig. 7.4). It is a major cellular redox system that maintains cysteine residues in the reduced state in numerous proteins. 

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