Some properties of mitochondrial glutathione.

1. The presence of GSH in rat liver mitochondria is confirmed. GSH diffuses from the suspended particles in the presence of phosphate but respiratory inhibitors inhibit the diffusion. 2. GSH is oxidised in situ by oxidants including t-butyl hydroperoxide. The products formed include GSSG and GSS-protein mixed disulphides. The oxidation occurs at lower oxidant concentrations if phosphate or oxaloacetate are also present. Respiratory inhibitors abolish their effect. 3. With phosphate, the GSSG produced is found chiefly outside the mitochondria whereas with oxaloacetate, it is found chiefly inside. 4. The GSSG formed by the oxidation is reduced by Krebs-cycle acids with the exception of the ketoacids. Exogenous GSSG is reduced by these substrates only after lysis. Intact particles, however, catalyse the reduction of GSSG by either NADH2 or NADPH2.