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

The isotope effect upon the binding constant of NADH to equine liver alcohol dehydrogenase is determined with a method in which the isotopic ratio is measured concurrently in the free and the bond form of the coenzyme, by use of a propellent-pressurized ultrafiltration apparatus for separation of the two. The value for KH/KD for the binding constants was 1.00 +/- 0.02 at pH 10.3 and 25 degrees C.