Search for a regulatory function of mitochondrial proteinases in yeast

AbstractProteolytic activity in yeast mitochondrial membranes and soluble fractions was studied using a labeled substrate: [14C]dimethylcasein. Optimal activity for the two fractions was at pH 6 in phosphate buffer at 37°C. Activity was partially inhibited by adding 3 mmol/1 ATP. Activity was enhanced rapidly in both fractions when yeast cells were grown aerobically on a derepression medium and transfered on a repression medium in anaerobiosis. Mitochondrial proteinase mediation in the mitochondrial breackdown observed during transition from aerobical derepression to anaerobical repression is discussed