Kinetic analysis of rat liver sorbitol dehydrogenase.
1. A steady state kinetic investigation was performed on an improved preparation of rat-liver sorbitol dehydrogenase (L-iditol: NAD-oxidoreductase, EC 1.1.1.14). 2. Data analyses indicate the enzyme follows a rapid equilibrium random mechanism in the direction of sorbitol oxidation and a random mechanism in the direction of fructose reduction. 3. Kinetic constants were: K m NAD 0.082 mM; K m sorbitol 0.38 mM; K m NADH 67 microns; K m fructose 136 mM. 4. Evidence is adduced to indicate the more rapid reverse (fructose reduction) reaction is susceptible to metabolic control by formation of abortive enzyme fructose-NAD and enzyme-NADH-sorbitol complexes.
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D007064:L-Iditol 2-Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D008099:Liver / Q000201:enzymology*; D008956:Models, Chemical; D009243:NAD / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D051381:Rats; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000302:isolation & purification*
D009243:NAD; D013401:Sugar Alcohol Dehydrogenases; D007064:L-Iditol 2-Dehydrogenase