ATP-dependent proteolysis in yeast mitochondria

• Published in: Journal of biochemistry (Tokyo) 1994, Vol.115 (6), p.1166-1171
• Main Authors: Yasuhara, T, Mera, Y, Nakai, T, Ohashi, A
• Format: Article
• Language: English
• Subjects: adenosine triphosphate; Adenosine Triphosphate - physiology; Animals; ATP; Electrophoresis, Polyacrylamide Gel; enzyme activity; Hemin - pharmacology; Hydrolysis; Indicators and Reagents; Mammals; mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondria - ultrastructure; Nucleotides - pharmacology; protease; Protein Biosynthesis; proteinases; Proteins - metabolism; proteolysis; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - ultrastructure; Species Specificity; yeast
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a124474

An ATP-dependent proteolysis system in yeast mitochondria was characterized by examining the hydrolysis of mitochondrial translation products in isolated mitochondria. Degradation of [35S]methionine-labeled polypeptides synthesized in isolated yeast mitochondria was activated by exogenously added ATP. ADP, GTP, and CTP substituted for ATP to some extent, but nonhydrolyzable ATP analogues did not. Adenosine-5'-O-(3'-thiotriphosphate) effectively competed with ATP as activator. Carboxyatractyloside, an inhibitor of adenine nucleotide translocation across the mitochondrial inner membrane, and the metal chelator o-phenanthroline inhibited the ATP-dependent proteolysis. The latter inhibition was abolished by subsequent addition of Mn2+ or Co2+ but not Ca2+ or Zn2+. Hemin inhibited the ATP-dependent proteolysis of mitochondrial translation products with a half-maximum inhibition at 12 micromolar. Analysis by SDS-polyacrylamide gel electrophoresis showed that [35S]methionine-labeled polypeptides were rapidly degraded into low-molecular-weight species. Submitochondrial particles retained the ATP-dependent proteolytic activity and had the same spectrum of inhibitors as intact mitochondria except for a reduced effect of carboxyatractyloside. These results indicate that yeast mitochondria contain an ATP-dependent and hemin-sensitive proteolysis system which is associated with the inner membrane and can hydrolyze mitochondrial translation products, and that a chelator-sensitive protease is probably involved in this system.