Relationship between Degradation Rates of Proteins in Vivo and Their Susceptibility to Lysosomal Proteases

Abstract

Abstract The pool of soluble proteins of rat liver has been labeled with [3H]leucine and [14C]leucine in such a way that the 3H is predominantly in the slowly turning over proteins and the 14C is predominantly in the rapidly turning over proteins. This doubly labeled pool of proteins has been subjected to proteolysis by lysosomal extracts. From the differential rate of release of the isotopes into trichloroacetic acid-soluble form, it is evident that there is a direct correlation between protein degradation rates in vivo and their susceptibility to lysosomal proteolysis.