Reversal by Phosphate of Glucose Repression of Catalase Synthesis in Saccharomyces cerevisiae

Abstract

IT has long been known that glucose represses many inducible enzyme systems¹. The mechanism responsible for this specific effect has elicited wide interest although none of the suggestions put forward has received unqualified acceptance. Neidhart and Magasanik² and Mandelstam^3,4 have concluded from their studies on β-galactosidase that any compound utilized by the organism as a source of energy and carbon can act as repressor and that it may not be glucose itself but a catabolite derived from it that is the active repressor. According to the “feedback hypothesis” of Neidhart and Magasanik⁵ and Vogel⁶, the formation of each catabolic enzyme is controlled by the intracellular concentration of some particular metabolite which is an immediate or ultimate product of that enzyme and which is also produced from glucose at a rate faster than its utilization for synthetic reactions in the cell. A possible site of glucose action is the release of the enzyme from the RNA template⁷ or ribosome⁸.