Glucose and Polyol Transport Systems in Candida intermedia and their Regulation

SUMMARY: Transport systems for glucose in the yeastCandida intermedia were compared in cells grown under different conditions. Under conditions of glucose repression the yeast formed a facilitated diffusion system. with a half-saturation constant (Km) of 2.0 mM. When grown under derepression conditions a H+ glucose symport was formed (Km 0.16 mM) that was also able to transport L-sorbose and sorbitol (Km about 200 mM). A H+ polyol symport that could transport sorbitol, xylitol, D-arabinitol and mannitol was formed when the cells were grown on sorbitol. This system did not transport glucose. Transport of polyols was not observed when C. intermedia was grown on glucose even when sorbitol was present in the medium.