Carbon catabolite repression of maltase synthesis in Saccharomyces carlsbergensis.

Carbon catabolite repression of maltase gene expression is brought about by the addition of glucose, resulting in a drastic inhibition of the induction of maltase. When added to induced cells, glucose leads to the inhibition of maltase synthesis within 30 min, which can be accounted for by the disappearance of hybridizable maltase RNA sequences. The loss of maltase-specific RNA due to catabolite repression can be traced to the combined effects of a 15-fold decrease in the rate of transcription of the maltase structural gene 15 to 20 min after the addition of glucose and a change in the half-life of maltase mRNA. However, the stability of maltase, once induced, is not affected by the addition of glucose.