Abstract
The process of dererioration of the ordinary muscle of sardine, Sardinops melanosticta, during ice-storage was studied by the measurements of myofibrillar ATPase activities, subunit composition, and other properties
Myofibrillar EDTA-ATPase activity lost about 70% after 1 day-storage in ice. Ca2+-and Mg2+-ATPase activities decreased to 50%-40% of their initial levels after 6 day-storage, while Mg2+-ATPase activity in the presence of EGTA increased and then decreased. A similar change in ATPase activities was observed when the isolated myofibrils were stored in a solution at pH 6.0, whereas little change occurred in the ATPase activities at pH 7.0
Subunit composition of the myofibrellar proteins with exception of myosin showed little change during ice-storage, while some degradation of myosin heavy chain due to proteolysis was observed
A specific sarcoplasmic protein was insolubilized readily within the 1 day-storage of muscle.
