title: The kinetics of the interconversion of intermediates of the reaction of pig muscle lactate dehydrogenase with oxidized nicotinamide-adenine dinucleotide and lactate.
abstract: Oxamate competes with pyruvate for the substrate binding site on the E(NADH) complex of pig skeletal muscle lactate dehydrogenase. When this enzyme was mixed with saturating concentrations of NAD(+) and lactate in a stopped-flow rapid-reaction spectrophotometer there was no transient accumulation of enzyme complexes with the reduced nucleotide. The steady-state rate of formation of free NADH was reached within the dead-time of the instrument (3ms). When oxamate was added to inhibit the steady state and to uncouple the equilibration: [Formula: see text] through the rapid formation of E(NADH) (Oxamate), the rate of formation of E(NADH) could be measured by observation of the first turnover. This pH-dependent transient is controlled by the rate of dissociation of pyruvate and the fraction of the enzyme in the form E(NADH) (Pyruvate).
mesh_terms: D000818:Animals; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D013053:Spectrophotometry; D013552:Swine
chemical_list: D007773:Lactates; D011773:Pyruvates; D009243:NAD; D007770:L-Lactate Dehydrogenase