Inactivation of Myosin ATPase by Condensed Polysilicic Acid Powders

抄録

Myosin ATPase [ATP phosphohydrolase, EC 3. 6. 1. 3] from rabbit skeletal muscle was inactivated by quartz, mica, talc and other silicate minerals which were added to the incubation medium for the enzymatic reaction. The extent of ATPase inac-tivation by these condensed polysilicic acids was correlated to the amounts of ex-changeable hydrogen on the surface, to the surface area and to the species of poly-silicic acids. The powders of mica, talc and quartz inactivated ATPase more intensely than those of rhodonite, sillimanite and diopside in an equal amount. It was shown that the surface of the polysilicic acid powder for adsorption of myosin rather than the silicic acids dissolved in the medium is responsible for the ATPase inactivation. The inactivation was discussed in relation to the surface area, the ion-exchange capacity and the crystal structure of the polysilicic acids.