Effect of muscle lysosomal enzymes and calcium activated neutral proteinase on myofibrillar ATPase activity: Relationship with ageing changes.

Myofibrillar ATPase activities have been used to study the in vitro effect of Ca-ANP (Calcium Activated Neutral Proteinase) and lysosomal proteolytic enzymes on the myofibrils at their respective optimal conditions activity. It appeared that the effect of Post-mortem ageing of meat on the MgCa and Mg-EGTA modified ATPase activities can be reproduced by incubating myofibrils with these hydrolytic systems. However, the effect of ageing on the Ca(++)-enhanced ATPase activity of myofibrils was not explained. It was concluded that Ca-ANP and at least one lysosomal thiol protease could be involved in the ageing process.