Conflicting data have been reported concerning the anomeric specificity of glucokinase. In the present study, liver hexokinase (Km for D-glucose 0.4 mM) displayed a higher affinity for but lower Vmax. with α- than with β-D-glucose. The velocity of the reaction catalysed by liver glucokinase was higher with with β- than with α-D-glucose, whatever the glucose concentration. The apparent Km of glucokinase was somewhat lower, however, with α- than with β-D-glucose. Comparable results were obtained for the high-Km glucokinase-like enzymic activity present in normal pancreatic islets or insulin-producing tumoral cells. These results suggest that the anomeric specificity of glucokinase cannot account for the higher rate of glycolysis found in islets exposed to α- as distinct from β-D-glucose.
Anomeric specificity of hexokinase and glucokinase activities in liver and insulin-producing cells
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A Sener, M H Giroix, S P Dufrane, W J Malaisse; Anomeric specificity of hexokinase and glucokinase activities in liver and insulin-producing cells. Biochem J 1 September 1985; 230 (2): 345–351. doi: https://doi.org/10.1042/bj2300345
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