RECIPROCAL EFFECTS OF 2-FLUORO-2-DEOXY-D-GLUCOSE AND GLUCOSE ON THEIRMETABOLISM IN SACCHAROMYCES-CEREVISIAE STUDIED BY MULTINUCLEAR NMR-SPECTROSCOPY

The effects of various concentrations of 2-fluoro-2-deoxy-D-glucose (F DG) on the aerobic metabolism of glucose and the reciprocal effect of glucose on the metabolism of FDG in glucose-grown repressed Saccharomy ces cerevisiae cells were studied at 30 degrees C in a standard pyroph osphate medium containing 5 x 10(7) cells/ml by H-1-, F-19-, P-31-NMR and biochemical techniques. The glucose consumption rate is reduced by about 57% and 71% in the presence of 5 mM FDG and 10 mM FDG respectiv ely. Under the same conditions, the ethanol production rate also decre ases about 54% and 68%, respectively. When FDG is the unique carbon so urce, the alpha- and beta-anomers of 2-fluoro-2-deoxy-D-glucose-6-phos phate (FDG6P) and a much smaller quantity of 2-fluoro-2-deoxy-gluconic acid (FDGA) were observed. The quantities of alpha- and beta-FDG6P re ach their maximum values within 1 h of incubation and then decrease co ntinuously. In contrast, Glc favors the consumption of FDG and the syn thesis of FDG6P and uridine-5'-diphosphate fluoro-deoxy-glucose (UDP-F DG). In the presence of Glc, FDG6P reaches a plateau after 1 h or 2 h of incubation while UDP-FDG increases regularly with time. Apart from trehalose, no other disaccharide such as fluoro-dideoxy-trehalose (FDG -FDG) or fluoro-deoxy-trehalose (FDG-Glc) were observed. Thus, in cont rast to UDP-Glc, UDP-DG, Glc6P and DG6P, UDP-FDG and FDG6P are not goo d substrates for trehalose-6-P synthetase. The effect of DG and FDG on the cell growth in standard nutrient media was also investigated at 3 7 degrees C. The cell growth was found to be completely inhibited upon addition of 1 mM FDG and only slowed down in the presence of 1 mM DG. In the latter case, the doubling time tau is about 3 h instead of 1 h 25' in the absence of DG and FDG. The reciprocal effects of FDG and G lc on their metabolism, the toxicity of FDG and the blockage level of enzymes induced by FDG are discussed in comparison with 2-deoxy-D-gluc ose (DG) and Glc. The above results clearly show that the metabolism a nd the toxicity of a drug strongly depend on the physiological state o f cells.