Two kinetic methods to study the regulation of mammalian hexokinases.
Two new kinetic analyses for mammalian hexokinases are presented, which permit one to study the regulation of these enzymes by product inhibition. One method uses the pyruvate kinase-coupled assay and the other the glucose-6-phosphate dehydrogenase-coupled assay. Both methods give simple linear plots, which indicate that the magnesium-ATP complex overcomes the glucose 6-phosphate inhibition competitively, but by atypical kinetics. A new regulation coefficient (Kr) was defined and it was shown that, with both assay methods, the reciprocals of the slopes of the simple linear plots are proportional to Kr.[Mg.ATP].NADP, but not NAD, was found to be a powerful inhibitor of pig heart hexokinase.
Jenkins
W T
WT
Department of Chemistry, Indiana University, Bloomington 47405.
Thompson
C C
CC
D000818:Animals; D006593:Hexokinase / Q000378:metabolism*; D007700:Kinetics; D008433:Mathematics; D008722:Methods; D008962:Models, Theoretical; D009206:Myocardium / Q000201:enzymology; D013552:Swine
D006593:Hexokinase