Fermentative Phosphorylation of Glucosamine by Yeast

Phosphorylation of glucosamine was investigated under the conditions of yeast fermentation (dissolution of glucose). Air-dried cell preparation of baker's yeast was used as enzyme source of fermentation and phosphorylation of glucosamine. By use of the energy derived from glucose dissolution, 20 mM of Gm 6-P were formed during 8 hr of incubation. FBP, an intermediate of glycolysis, was found to be a suitable energy source than glucose in both efficiency of energy transference to glucosamine and rate of Gm 6-P formation. A higher concentration of phosphate ion was required in the reaction mixture which contains glucose than that required in the reaction mixture containing FBP. Initiation of glucosamine phosphorylation in the reaction mixture containing glucose was closely related to the amount of glucose added. Gm 6-P formation was initiated immediately before the maximum accumulation of FBP and proceeded simultaneously with the degradation of accumulated FBP. Formation of Gm 6-P continued until FBP was consumed. The remarkable catalytic action of an added ATP was observed in both glucose and FBP systems.