title: Subunit structure and kinetic properties of L-beta-hydroxy acid dehydrogenase of Drosophila.
abstract: L-beta-hydroxyacid dehydrogeanse (L-gulonate:NAD+ 3-oxidoreductase, EC 1.1.1.45) of Drosophila is made up of two non-identical subunits with molecular weights of 40 000 and 23 500. Michaelis constants calculated at saturating concentrations of the other substrate were 0.13 mM for NAD+, 0.85 mM for L-gulonate, 14.8 mM for L-beta-hydroxybutyrate; dissociation constants (Kia) were 2.8 mM for L-gulonate, 22 mM for L-beta-hydroxybutyrate. The maximum velocity with L-gulonate as substrate was ten-fold greater than with beta-hydroxybutyrate. As product inhibitors, both NADH and acetoacetate are competitive vs. both substrates, suggesting a rapid equilibrium random mechanism.
mesh_terms: D000818:Animals; D002237:Carbohydrate Dehydrogenases; D055598:Chemical Phenomena; D002621:Chemistry; D004331:Drosophila melanogaster / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006884:Hydroxybutyrate Dehydrogenase / Q000378:metabolism; D007700:Kinetics; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013400:Sugar Acids
chemical_list: D013400:Sugar Acids; D009243:NAD; D009249:NADP; D010088:Oxidoreductases; D002237:Carbohydrate Dehydrogenases; D006884:Hydroxybutyrate Dehydrogenase