An Inducible System for the Hydrolysis and Transport of β-Glucosides in Yeast I

• Published in: The Journal of general physiology Vol. 48; no. 5; pp. 873 - 886
• Main Author: Kaplan, J. Gordin
• Format: Journal Article
• Language: English
• Published: The Rockefeller University Press 01.05.1965
• ISSN: 0022-1295; 1540-7748

A strain of bakers' yeast was isolated which could utilize cellobiose and other β- D -glucosides quantitatively as carbon and energy sources for growth. Cellobiose-grown cells contained a largely cryptic enzyme active against the chromogenic substrate p -nitrophenyl-β- D -glucoside. The patent (intact cell) activity of such cells was inhibited by azide and, competitively, by cellobiose; neither agent inhibited the β-glucosidase activity of lysed cells or of extracts. The enzyme induced by growth in cellobiose medium had no affinity for cellobiose as either substrate or inhibitor; its substrate specificity classifies it as an aryl-β-glucosidase. It was concluded that growth in cellobiose also induced the formation of a stereospecific and energy-dependent system whose function determined the rate at which intact cells could hydrolyze substrates of the intracellular β-glucosidase.