The noninvolvement of MDH as NAD-oxidoreductase shuttle in rat liver peroxisomes

Subcellular localization of malate dehydrogenase and glycerol-3-phosphate dehydrogenase in rat liver was studied by sucrose density gradient centrifugation. The specific adsorption of cytosolic malate dehydrogenase to the peroxisomes was observed. This phenomenon was eliminated by washing peroxisome-rich fraction with 100 mM potassium chloride. It is suggested that the malate shuttle between the cytosol and the mitochondria is more dominant than the glycerophosphate shuttle with respect to the transfer of reducing equivalents, while NADH produced by fatty acid oxidation in peroxisomes can not be transferred into the cytosol via the malate shuttle in the rat liver.