Regulation of sterol biosynthesis in yeast: Induction of 3-hydroxy-3-methylglutaryl-CoA reductase by glucose

Abstract

Anaerobically cultured yeast cells have a very low HMG-CoA reductase activity and a low sterol content. When these cells are transfered to phosphate buffer containing 1.2 % glucose and held under aerobic conditions, the specific activity of the HMG-CoA reductase increases up to sixfold within 8 hrs. The increase in the reductase activity is paralled by an increase in the sterol content. This induction of HMG-CoA reductase in resting yeast cells is inhibited by cycloheximide indicating that a de novo synthesis of enzyme protein is mediated by glucose under aerobic conditions. It appears that the regulation of sterol synthesis in yeast is closely connected with the aerobic glucose metabolism.