抄録
The denaturation of carp myosin B (in the presence of 0.6M KCl) during the slow freezing process where a gradual increase in salt concentration occurs by freezing point depression, was investigated in comparison with that of the quick freezing sample. Changes in Ca-and Mg-ATPase activities showed that the binding ability between myosin and actin was weakened by the exposure to the concentrated salt solution. When the samples were rapidly frozen to -20°C at an appro-priate point during the slow freezing process and then stored at -20°C, the apparent rate con-stants for the freeze denaturation were equalled, regardless of the freezing process. The apparent rate constant for the thermal inactivation of myosin B sampled at the appropriate point on the slow freezing curve showed a two-phased first-order inactivation mode after the first moment of arrival at the eutectic point. And the single-phased first-order inactivation mode was restored by the addition of carp F-actin to its myosin B. This phenomenon shows that a portion of F-actin in myosin B was denatured as a result of the exposure to the concentrated salt solution. However, the two-phased mode of thermal inactivation was not observed in the quick freezing sample.
