Similarities in protein synthesis and degradation in normal and dystrophic muscle cultures

Protein synthesis and degradation were compared in cultured muscle cells obtained from normal and dystrophic chick embryos under conditions where labeled amino acid reincorporation was not a complicating factor, where fibroblast contamination was minimized, and where the animals compared were as genetically similar as possible. Under these conditions both cell types exhibited a half-time of protein turnover of 34 h. Degradation in both was inhibited 21% by leupeptin (50 μg/ml), and both showed parallel increases in degradation rates under ‘step-down’ conditions.