Kinetic analysis of lactate dehydrogenase using integrated rate equations

The reaction catalyzed by lactate dehydrogenase was analyzed under fully second-order conditions using integrated rate equations. A two-step regression analysis was utilized to fit twenty-one progress curves repeated in sextuplicate to the general mechanism second-order integrated rate equation with additional terms for substrate inhibition. The fitting error was less than one percent. The resulting kinetic constants support a ternary complex mechanism; in no case were constants supporting another mechanism predicted. The inhibition constant for oxamate was also determined.