Incorporation of amino acids into the protein of isolated mitochondria. A search for optimum conditions and a relationship to oxidative phosphorylation

Abstract

Isolated rat-liver mitochondria incorporate labelled amino acids into protein when incubated in the presence of PO4 3-, Mg2+, K+ and Na+ ions with an oxidizable substrate and a supply of adenine nucleotide. Addition of cell sap was not necessary, provided that a mixture of amino acids was supplied. The optimal concentrations of Mg2+, K+ and Na+ ions for amino acid incorporation were determined. Evidence was produced that the amino acid incorporation into protein of mitochondria was not caused by contaminating microsomes or bacteria. It was stimulated by preincubation of the mitochondria with ribonuclease. The rate of incorporation of amino acids was shown to be correlated with the efficiency of the production of energy by oxidative phosphorylation.