Molecular-size-dependent degradation of liver cytosolic proteins in vitro.

Degradation of rat liver cytosolic proteins at a neutral pH in the presence of 0.1% SDS was demonstrated by SDS-acrylamide gel electrophoresis. This proteolysis in vitro mimics molecular-size-dependent proteolysis in vivo; larger proteins were degraded more rapidly than smaller ones. Evidence is presented that the proteolysis is not due to contaminating lysosomal cathepsins in the cytosol.