SUGAR TRANSPORT IN A PSYCHROPHILIC YEAST

Abstract

The mechanism and temperature characteristic for sugar transport were compared in a psychrophilic and a mesophilic yeast. Between 0 and 10 C, glucose utilization, glucosamine accumulation, and sorbose transport showed a very high temperature characteristic in the mesophile ([mu] = 50,000) compared with the psychrophile ([mu] = 12,000). Hexokinase activity in cell-free extracts from both yeasts, however, showed the same low temperature characteristic ([mu] = 15,000). Although the temperature characteristic for sugar transport was markedly different for the mesophile and the psychrophile, sugar transport in both yeasts met the criteria for carrier-mediated facilitated diffusion.