Abstract
Investigations were carried out into the problems of the effects of action on the solubility of myosin and the relationship between actomyosin-ATP interaction and the solubility of actomyosin. Particular considerations were paid to the relationship of the above to the alkaline and isoelectric precipitation of myosin. The present paper further deals with the relationship between the alkaline precipitation and the “phenomenon of dual precipitation, ” which has been reported with respect to actomyosin.
The results obtained are as follows:
(1) The precipitation zone of actomyosin, which has been considered to be isoelectric, is not composed of a single but two precipitation zones ; one is of acid side (perhaps isoelectric)-aggregation zone (AM) I, and the other is of alkaline side (perhaps non-isoelectric)-aggregation zone (AM) II. Between these zones, there is a zone of relatively higher solubility (intermediate zone (AM)). The particles in the zone of acid side are coarse, while those of the alkaline side are fine.
(2) Syneresis in superprecipitation is more intense in the aggregation zone (AM) I and II, especially in the latter, and is less intense in the intermediate zone (AM). Gelation appears in the alkaline side of the aggregation zone (AM) II.
(3) The above-mentioned results seem to suggest the importance of the property of the aggregation zone (AM) II, which is formed on the basis of the alkaline precipitation of myosin in the formation of superprecipitation and gelation.
(4) The alkaline precipitation is caused even under the existence of PP or of ATP. In these cases, KCl concentration at which this precipitation appears is decreased with the increase of the concentration of PP or of ATP.
phenomenon of dual precipitation are noted in myosin at pH 7 under the existence of PP or ATP. This seems to indicate that the mechanism of the “phenomenon of dual precipitation” is different from that of the alkaline pre cipitation.
(6) In myosin, no syneresis due to PP or ATP, especially to the latter, is formed.
