Abstract
A technique is described for the analysis of degradation rates of individual intracellular proteins, based on pulse-chase-labeling of cells using radioactive amino acids [35S]methionine, two-dimensional polyacrylamide gel electrophoresis, fluorography and scanning of the fluorograms by a computerized video densitomter. As compared to scintillation counting of individual protein spots resolved by two-dimensional gel electrophoresis, this method allows a rapid and precise determination of the degradation rates of individual intracellular proteins. In the present study, degradation rates of individual intracellular proteins of normal human skin fibroblasts and skin fibroblasts from patients with Duchenne muscular dystrophy were compared. Rates of degradation for proteins PIIa, PIIb and PIIc recently described as cell-type-specific proteins were significantly enhanced (p > 0.01) in fibroblast cultures of Duchenne muscular dystrophy origin.