The Catalase Requirement in the Reversal of Mitochondrial Swelling Caused by Reduced Glutathione and by Trace Metals

Abstract

Abstract The requirement of a contraction factor such as catalase in adenosine triphosphate-dependent reversal of glutathione-induced swelling of rat liver mitochondria has been re-examined in view of the tiding of Cash and Gardy (11) that commercial samples of reduced glutathione contain sufficient iron, copper, and calcium to account for their swelling activity. Fe++, Cu++, and Ca++, tested in the absence of GSH, were found to cause swelling of rat liver mitochondria in concentrations in which they may be present as contaminants in commercial GSH preparations. However, ATP + Mg++ + bovine serum albumin readily reversed mitochondrial swelling caused by these metals; additions of crystalline catalase were not required, nor did they influence the rate or extent of the reversal significantly. On the other hand, swelling caused by commercial GSH preparations, or by mixtures of GSH and metal ions, was not reversed by ATP, Mg++, and bovine serum albumin unless crystalline catalase was added. Contaminating Fe++, Cu++, or Ca++ ions may therefore be the actual causative agents for mitochondrial swelling produced by commercial GSH preparations. However, if this is the case, the findings show that the presence of GSH so modifies the course of the swelling that it cannot be reversed by ATP + Mg++ + bovine serum albumin unless catalase (contraction factor II) is also present.