INDUCTION OF ALDOSE REDUCTASE AND XYLITOL DEHYDROGENASE-ACTIVITIES INCANDIDA-TENUIS CBS-4435

Ln this study the ability of various sugars and sugar alcohols to indu ce aldose reductase (xylose reductase) and xylitol dehydrogenase (xylu lose reductase) activities in the yeast Candida tenuis was investigate d. Both enzyme activities were induced when the organism was grown on D-xylose or L-arabinose as well as on the structurally related sugars D-arabinose or D-lyxose. Mixtures of D-xylose with the more rapidly me tabolizable sugar D-glucose resulted in a decrease in the levels of bo th enzymes formed. These results show that the utilization of D-xylose by C. tenuis is regulated by induction and catabolite repression. Fur thermore, the different patterns of induction on distinct sugars sugge st that the synthesis of both enzymes is not under coordinate control.