Proteolytic Activity of Skeletal Muscle of Normal and Dystrophic Chickens and Rabbits

Abstract

Summary. Autolysis of skeletal muscle of rabbits and chickens was demonstrated by a colorimetric ninhydrin procedure. Evidence is presented for the enzymatic and proteolytic nature of the reaction. In skeletal muscle of chickens with a hereditary form of muscular dystrophy or of rabbits with muscular dystrophy resulting from a vitamin E-deficiency, large increases in autolytic activity were found. Autolytic activity was also increased several fold by the addition of purified muscle cathepsin D which indicates that this enzyme is probably involved in autolysis of muscle. These studies suggest that the elevation in the activity of the proteolytic enzymes may be a major factor in the muscle-wasting process characteristic of muscular dystrophy.