Quantitative Studies on the Soluble Compartments of Light and Heavy Mitochondria from Rat Liver.

Previous studies in our laboratories had shown that sarcosine dehydrogenase and dimethylglycine dehydrogenase are exclusively mitochondrial enzymes and that they can be liberated from mitochondria by sonic irradiation (2, 3). By employing the N-methyl-oxidizing enzymes as markers, the rates and extent of release of various mitochondrial components during sonic irradiation have been measured. Prom such analyses it has been possible to define more quantitatively the size and composition of the soluble compartment of the mitochondrion. It has been demonstrated also that sarcosine dehydrogenase, located exclusively in the soluble compartment, provides a convenient marker for distinguishing “heavy” and “light” mitochondria.