Isotope effects in the binding of NADH to equine liver alcohol dehydrogenase

Abstract
The isotope effect upon the binding constant of NADH to equine liver alcohol dehydrogenase [EC 1.1.1.1] is determined with a method in which the isotopic ratio is measured concurrently in the free and the bound form of the coenzyme, using a propellent-pressurized ultrafiltration apparatus for separation of the two. The value for KH/KD [binding constant for Proton/binding constant for deuteron] was 1.00 .+-. 0.02 at pH 10.3 and 25.degree. C.