A sensitive method for measuring protein turnover based on the measurement of 2-3H-labelled amino acids in protein

Abstract

A method for measuring the rate of protein degradation was described. The method measured the change in 2-3H content of protein with time by racemization of the protein hydrolysate with acetic anhydride. The 3H on C-2 of amino acids was stable in proteins but became labile, owing to the action of transaminases, once the amino acids were released by proteolysis. The specific measurement of 2-3H in amino acids largely overcame problems due to compartmentation and isotope recycling, and evidence to support this claim was presented. Values for the half-life of Lemna minor (duckweed) protein determined by the new method were compared with values obtained by other methods.