The Control of Alcohol Dehydrogenase Isozyme Synthesis in Saccharomyces cerevisiae

Abstract

Isozymes of alcohol dehydrogenase (ADH) from yeast were separated by discontinuous electrophoresis. Three major bands were observed: ADH-I, ADH-II, and a new band designated mito-ADH. Work with isolated mitochondria showed that the mito-ADH band could be produced from physiologically competent mitochondria by mechanical disruption or by treatment with detergents.The isozyme pattern was determined for the various physiological states of yeast growing anaerobically and aerobically on 2% glucose and aerobically on 2% ethanol, and for catabolite de-repressed cells undergoing an anaerobic → aerobic transition in continuous culture.The changing isozyme pattern substantiates the thesis that ADH-I is produced constitutively and that ADH-II is regulated via catabolite repression. It appears from the data that mito-ADH is more closely related to mitochondriogenesis than is ADH-II.