Two hexokinases were characterized in Schizosaccharomyces pombe: hexokinase 1, with a low phosphorylation coefficient on glucose (Km 8.5 mM) and hexokinase 2, a kinetically conventional hexokinase. Genes hxk1 + and hxk2 + encoding these enzymes were cloned and sequenced. Disruption of hxk1 + 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.
