Proton NMR measurements of hydrogen exchange at the C-3 position of 3-hydroxybutyrate in suspensions of rat liver mitochondria.

Rat liver mitochondria suspended in buffer made with 2H2O catalyse exchange C-3 proton of added D-3-hydroxybutyrate with solvent deuterons. The kinetics of this process can be followed using spin-echo proton NMR. The observed isotope exchange velocity is sensitive to the activity of D-3-hydroxybutyrate dehydrogenase, which is an integral protein of the inner mitochondrial membrane. A method is described which can be used to obtain the specific isotope exchange velocity of the enzyme in the intact mitochondrion.