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 (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.
Petit
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Instituto de Investigaciones Biomédicas del C.S.I.C., Unidad de Bioquímica y Genética de Levaduras, Madrid, Spain.
Blázquez
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MA
Gancedo
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D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D005632:Fructose / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism; D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases / Q000378:metabolism; D006593:Hexokinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009249:NADP / Q000494:pharmacology; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D012568:Schizosaccharomyces / Q000201:enzymology*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D012333:RNA, Messenger; D005632:Fructose; D009249:NADP; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase; D006593:Hexokinase; D005947:Glucose