Ca‐activated neutral protease and its inhibitors: In vitro effect on intact myofibrils

Abstract
SDS gel electrophoresis of troponin and myosin extracted from chicken myofibrils pretreated with Ca‐activated neutral protease showed a pattern similar to that observed in the muscles of patients with Duchenne muscular dystrophy, that is, a decrease in troponin‐l and troponin‐C with relative preservation of troponin‐T and degradation of the heavy chain of myosin. Also, α‐actinin and troponin‐C were released from myofibrils. Two inhibitors of Ca‐activated neutral protease, leupeptin and E‐64, inhibited the degradative action of Ca‐activated neutral protease on intact myofibrils in vitro.