1963 年 29 巻 6 号 p. 537-541
Change in the intrinsic viscosity of purified fish actomyosin caused by heating at various temperatures was dealt with. Shimizu, Hosokawa and Simidu, who investigated the apparent viscosity of a concentrated fish muscle protein extract, found a remarkable increase in the viscosity at temperature range between 30°C.-40°C. and ascribed it to unfolding of the actomyosin molecule. In the present paper, it was become clear from following results that this phenomenon is not due to the change in the configuration of the protein molecule itself, but to the alternation in the interaction of the unfolded molecules.
When dilute solution of fish actomyosin was heated, the intrinsic viscosity always decreased even at temperatures between 30°C. and 40°C. at which the increase of the apparent viscosity was observed with the concentrated muscle extract. (Fig. 1)
The rate of the decrease was dependent on both the heating temperature and period. Continuing the heating for a long time, a considerable decrease was detectable even at temperatures lower than 30°C. (Fig. 3)
The change in the intrinsic viscotity caused by heating was found to be reversible to a certain extent by cooling (Fig. 2).