Abstract
Carp myosin was found to be digested easily at optimal pH of 7.0 and in the presence of >0.3mM calcium ion, once heat-treated. This process was biphasic, consisting of two apparent first-order processes with fast and slow rate constants. Both rate constants were significantly increased with increase in heating time and temperature, and consequently, with a progress in denaturation of myosin as measured by Ca- or EDTA-ATPase activity and in formation of ag-gregates.
It was also observed that a component with an Mr of 150, 000 (150K) was produced mainly from myosin heavy chain.
It was therefore suggested that the increasing susceptibility of myosin heavy chain to pro-teolysis to form the 150K component by calpain is closely related to heat-induced conformational changes of myosin.
