Interconversion and glucose-induced inactivation of glucose transport systems in Candida shehatae.

During starvation (derepression) glucose-grown cells of Candida shehatae IGC 3607 displayed total interconversion of facilitated diffusion of glucose into a glucose-proton symport, dependent on de novo protein synthesis (proteosynthetic interconversion). The reverse process, inactivation of the proton symport induced by glucose or 2-deoxyglucose, was not accompanied by reemergence of the facilitated diffusion function. The inactivation process had a rapid initial and a slow second phase. The rapid inactivation depended on the external sugar concentration and was reversible while the subsequent slow inactivation was irreversible and independent of the external concentration of the signalling sugar. Interaction of the latter with a surface receptor was indicated by the range of sugar concentrations that affected rapid inactivation.