Biochemical changes in progressive muscular dystrophy: VIII. Protein synthesis in skeletal muscle of mouse as a function of muscular dystrophy

Abstract

Poly-U-stimulated incorporation of phenylalanine by the ribosomes of normal and dystrophic mouse skeletal muscle was studied. Ribosomes from the dystrophic muscle responded much more actively to the addition of poly-U than the controls. Synthesis of protein/the synthesis of polyphenylalanine ratio (which roughly represents polysomes/monosomes ratio) showed decrease in the polysomal contents of the dystrophic muscle as compared to the normal. It was observed that the dystrophic muscle pH 5-enzyme was more active for the synthesis of protein than that of the normal. Sucrose density-gradient profiles showed a considerable decrease in the polysomal concentration of the dystrophic muscle, as compared to normal. Addition of 200 μg of poly-U restored the polysomal concentration of the dystrophic muscle to that of control. The majority of polysemes in both types of muscles disappeared on the addition of 10 μg of RNAse.