Metabolic Interconversion of Enzymes 1975

Three parameters participating in the specific control of proteolytic processes in intact yeast cells are discussed: (1) different substrate specificity of the yeast proteinases A and B, and carboxypeptidase Y when tested with yeast enzymes as substrate, (2) three types of macro molecular inhibitors from yeast specifically inhibiting the three pro teinases, (3) subcellular localization of the proteinases in the vacu oles and of the inhibitors in the cytosol. Mechanisms of a selective proteolysis of single enzymes or a group of enzymes dependent on chan ges in the physiological conditions are discussed. References Betz, H., Hinze, H., Holzer, H.: Isolation and properties of two inhibitors of proteinase B from yeast. J. Bioi. Chem. 249, 4515-4521 (1974) Cabib, E., Farkas, V.: The control of morphogenesis: An enzymatic mechanism for the initiation of septum formation in yeast. Proc. Nat. Acad. Sci. U.S. 68, 2052-2056 (1971) Cabib, E., Keller, F.A.: Chitin and yeast budding. J. Bioi. Chem. 246, 167-173 (1971) Cabib, E., Ulane, R.: Chitin synthetase activating factor from yeast, a protease. Biochem. Biophys. Res. Commun. 50, 186-191 (1973) Hasilik, A.: Inactivation of Chitin Synthase in Saccharomyces cerevisiae. Arch. Microbiol. 101, 295-301 (1974) Hasilik, A., Holzer,~: PartiCipation of the tryptophan synthase inactivating system from yeast in the activation of chitin synthase. Biochem. Biophys. Res.