The osmotic responses of Saccharomyces cerevisiae in K⁺-depleted medium

Saccharomyces cerevisiae showed reduced growth in a K⁺-depleted medium but was still capable of synthesizing and accumulating glycerol in the presence of 2.28% (w/v) NaCl; glycerol levels were similar in both K⁺-replete and K⁺-depleted media. The activity of glycerol-3-phosphate dehydrogenase, a key enzyme of glycerol synthesis, was inhibited to a similar extent by exogenous K⁺ and Na⁺ although such effects may be modified in vivo due to ionic compartmentation within the vacuole. These results indicate that exogenous K⁺ does not play a significant role in the initiation of glycerol synthesis in osmotically-stressed yeast.