OVERPRODUCTION OF ACETYL-COENZYME-A SYNTHETASE ISOENZYMES IN RESPIRING SACCHAROMYCES-CEREVISIAE CELLS DOES NOT REDUCE ACETATE PRODUCTION AFTER EXPOSURE TO GLUCOSE EXCESS

To investigate whether the production of acetate which occurs after ex posure of respiring Saccharomyces cerevisiae cells to excess glucose c an be reduced by overproduction of acetyl-CoA synthetase (ACS, EC 6.2. 1,1), the ACS1 and ACS2 genes were introduced on multi-copy plasmids. For each isoenzyme, the level in glucose-limited chemostat cultures wa s increased by 3-6-fold: relative to an isogenic reference strain. How ever, ACS overproduction did not result in a reduced production of ace tate after a glucose pulse (100 mmol l(-1)) to these cultures. This in dicates that a limited capacity of ACS is not the sole cause of acetat e accumulation in S. cerevisiae. (C) 1998 Federation of European Micro biological Societies. Published by Elsevier Science B.V. All rights re served.