INHIBITION BY POLYOLS OF THE HEAT-SHOCK-INDUCED ACTIVATION OF TREHALASE IN THE YEAST ZYGOSACCHAROMYCES-ROUXII

Trehalase activity was markedly enhanced in Zygosaccharomyces rouxii u pon exposure of the cells to a heat shock. The increase in trehalase w as independent of rapid changes in the intracellular concentration of cAMP and was not blocked by inhibitors of protein synthesis. Trehalase activated in vivo by heat shock was deactivated in vitro by phosphata se, suggesting that heat stress triggers a cAMP-independent signalling pathway that includes the activation of trehalase by phosphorylation of the enzyme protein. The addition to these cells before heating of e ither glycerol or other polyols produced a significant decrease in the heat-shock induced activation of trehalase. However, the trehalose co ntent in cells heat-shocked in the presence of polyols did not increas e significantly, indicating that these compounds may also influence th e synthesis of the disaccharide.