Novel Kefir yeast having remarkable sugar utilization. Part II. Hexose-phosphorylating activities of Torulopsis holmii KY-5 isolated from Kefir grain.

Torulopsis holmii KY-5 isolated from Kefir grain had in its constitution two kinds of hexose phosphorylating enzymes: glucokinase and galactokinase, and also had inducible hexokinase induced only by fructose.Unless the hexokinase was induced in the yeast, the galactokinase activity was about 5~9 times as much as glucokinase activity, and therefore this resulted in the preferential utility of galactose over glucose.The induction of hexokinase by fructose was suggested by the inhibitory effects of 2deoxyglucose for the growth of fructose-grown cells.The hexokinase induction by fructose was also confirmed chromatographically and electrophoretically.