Kinetic formulations for the oxidation and the reduction of glyoxylate by lactate dehydrogenase.
Chicken liver lactate dehydrogenase (L-lactate : NAD+ oxidoreductase, EC 1.1.1.27) irreversibly catalyses the oxidation of glyoxylate (hydrated form) (I) to oxalate (pH = 9.6) and the reduction of (non-hydrated form) (II) to glycolate (pH = 7.4). (I) attaches to the enzyme in the pyruvate binding site and (II) attaches to the enzyme at the L-lactate binding site. The oxidation of (I) (pH = 9.6) is adapted to the following mechanism: (see book). The abortive complexes, E-NADH-I and E-NAD+-II, are responsible for the inhibition by excess substrate in the reduction and oxidation systems, respectively. When lactate dehydrogenase and NAD+ are preincubated, E-NAD+- NAD+ appears and causes inhibition by excess NAD+ in the glyoxylate-lactate dehydrogenase-NAD+ and L-lactate-lactate dehydrogenase-NAD+ systems; the second NAD+ molecule attaches to the enzyme at the L-lactate binding site.
D000818:Animals; D001665:Binding Sites; D002645:Chickens; D006016:Glycolates / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D009243:NAD / Q000494:pharmacology; D010070:Oxalates / Q000494:pharmacology; D010072:Oxamic Acid / Q000494:pharmacology; D010084:Oxidation-Reduction; D011485:Protein Binding; D011773:Pyruvates / Q000378:metabolism
D006016:Glycolates; D006038:Glyoxylates; D010070:Oxalates; D011773:Pyruvates; D009243:NAD; D007770:L-Lactate Dehydrogenase; D010072:Oxamic Acid