Binding of mitochondrial malate dehydrogenase to mitoplasts

Abstract

The binding of 14C-labeled bovine and porcine malate dehydrogenase (EC 1.1.1.37) to rat liver mitochondria and mitoplasts was examined. The bovine enzyme associated nonspecifically with isolated mitochondria and sonicated mitoplasts. Scatchard plot analysis suggested a specific binding to mitoplasts of the order of 5 pmol malate dehydrogenase/milligram of mitoplast protein. Porcine malate dehydrogenase dimer but not monomer exhibited a similar binding. The results are discussed in relation to the mechanism of uptake of the enzyme by mitochondria after synthesis on cytosolic ribosomes.