Structural and functional characteristics of membrane fractions from cardiomyopathic and dystrophic muscle

Subcellular fractions from ventricular muscle of the cardiomyopathic Syrian hamster and breast muscle from the dystrophic chicken were prepared by zonal centrifugation in sucrose gradients. This tenchnique permitted the analysis of a wide spectrum of subcellular particles prior to sedimentation, thus avoiding loss of activity through particle clumping. Substantial differences in the distribution of beta-glucuronidase and p-nitrophenyl-phosphatase in zonal fractions from myopathic and control tissues provided evidence for contamination of fractions containing fragmented sarcoplasmic reticulum by lysosomes. This contamination may contribute signifantly to the altered lipid composition and Ca2+ transport function of the myopathic preparations.