Schizosaccharomyces pombe possesses an unusual and a conventional hexokinase: Biochemical and molecular characterization of both hexokinases

Two hexokinases were characterized in Schizosaccharomyces pombe: hexokinase 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, Disruption of kxk1(+) had no effect on growth but disruption of hxk2(+) doubled the generation time in glucose, Spores carrying the double disruption hxk1(+) hxk2(+) did not grow on glucose or fructose after one week. Expression of hxk1(+) increased strongly during growth in fructose or glycerol, Expression of hxk2(+) was highest during growth in glycerol. A NADP-dependent glucose dehydrogenase was detected, but not a glucokinase.