SCHIZOSACCHAROMYCES-POMBE POSSESSES AN UNUSUAL AND A CONVENTIONAL HEXOKINASE - BIOCHEMICAL AND MOLECULAR CHARACTERIZATION OF BOTH HEXOKINASES

Two hexokinases were characterized in Schizosaccharomyces pombe: hexok inase 1, with a low phosphorylation coefficient on glucose (K-m 8.5 mM ) and hexokinase 2, a kinetically conventional hexokinase, Genes hxk1( +) and hxk2(+) encoding these enzymes were cloned and sequenced, Disru ption of kxk1(+) had no effect on growth but disruption of hxk2(+) dou bled the generation time in glucose, Spores carrying the double disrup tion hxk1(+) hxk2(+) did not grow on glucose or fructose after one wee k. Expression of hxk1(+) increased strongly during growth in fructose or glycerol, Expression of hxk2(+) was highest during growth in glycer ol. A NADP-dependent glucose dehydrogenase was detected, but not a glu cokinase.