Thermal Activation of Actomyosin Mg2+-ATPases from Flying Fish and Black Marlin Muscles

The effects of heat treatment (25°, 30°, 35°, 37°, and 40°C) on acto-myosin Mg²⁺-ATPase activity from flying fish and black marlin were studied with respect to setting of their meat pastes. The setting ability of flying fish had very high values but black marlin was low. Flying fish actomyosin Mg²⁺ATPase was activated more than three times by heating at 35°C, while the activation of black marlin was about two-thirds at 37°C. For acto-HMM ATPase, however, no appreciable difference in activation was observed between flying fish and black marlin. For both fishes, the acto-S-1 ATPase activities were not enhanced by the heat treatment. A possible role of myosin fragments in this activation is discussed.