Abstract
The effect of temperature on actomyosin-ATPase activity and superprecipitation was investigated in detail.
1) Actomyosin-ATPase activity increased in an approximately straight line up to 40°C, and dropped somewhat at 50°C.
2) Superprecipitation occurred from 0°C to 40°C, appearing strongest at 15-20°C. The grades in the final state of superprecipitation differ with varied temperatures.
3) Superprecipitation was inhibited from 20°C to 40°C, with the rise of temperature, in spite of increase of ATPase activity; in other words, there was a discrepancy between superprecipitation and ATPase activity with regards to temperature.
4) The above mentioned results are in approximate accordance with Yutasaka (5) and Nagai et al.(6).
5) Using the grade of superprecipitation and that of ATPase activity as the basis of the determination, experiments on the heat denaturation of actomyosin were performed. The reversibility of actomyosin with temperature was found under both conditions of the heat treatment for 15minutes at 40°C and for 1-3minutes at 50°C.
Based on these results, the mechanism of the above mentioned discrepancy between superprecipitation and ATPase activity with respect to temperature was discussed.
