Anomeric specificity of human liver and B-cell glucokinase: modulation by the glucokinase regulatory protein.

摘要: The anomeric specificity of the wild-type recombinant forms human liver and B-cell glucokinase was investigated using radioactive anomers d-glucose as tracers. With at equilibrium 30°C, maximal velocity, Hill number, Ks amounted, respectively, to 16 μmol min−1 mg−1, 1.8 6.9 mM in case glucokinase, 7.3 2.0 7.1 glucokinase. Whether 20–22 or Km were significantly lower with α-d-glucose than β-d-glucose both As a result these differences, reaction velocity higher low hexose concentrations, while opposite situation prevailed high concentrations. In presence 0.2 d-fructose 6-phosphate, regulatory protein caused concentration-related inhibition phosphorylation, such an effect fading out concentrations either relative that its protein. phosphorylation by appeared more resistant inhibitory action mediated Such phenomenon failed achieve statistical significance It is proposed this information, especially novel findings concerning difference number sensitivity protein, should be taken into account when considering respective contributions α- overall equilibrated