Jasper Lactate Final: Difference between revisions

Studies have shown that the reaction mechanism of LDH follows an ordered sequence. In order for lactate to be oxidized NADH must bind to the enzyme first followed by lactate. Several residues are involved in the binding of NADH, including <scene name='Jasper_Lactate_Final/250_final/1'>Lys 250</scene> and <scene name='Jasper_Lactate_Final/85_final/1'>Tyr 85</scene>. Once the NADH is bound to the enzyme, it is then possible for lactate to bind. Lactate binds to the enzyme between the nicotinamide ring and <scene name='Jasper_Lactate_Final/His_195_final/1'>His 195</scene>.  Transfer of a hydride ion then happens quickly in either direction giving a mixture of the two tertiary complexes, enzyme-NAD+-lactate and enzyme-NADH-pyruvate. Finally pyruvate dissociates from the enzyme followed by NAD+. The rate limiting step in this reaction is the rate of dissociation of NAD+. The same holds true in the reverse reaction that the coenzyme, NADH, must bind first before the substrate, pyruvate, can bind. The conversion of pyruvate to lactate with the subsequent regeneration of NAD+ is a very favorable(1).