[Nature of the changes in water-soluble enzyme activity in the action of injurious agents on the muscles. II. The change in the extractability of aldolase from muscles exposed to urea].

A study was made of solubilization of aldolase isolated from homogenates of skeletal muscles, both intact and being in the state of contracture due to urea action. Compared to water, electrolytes extract more aldolase from homogenates of intact and altered muscles. Almost the same amounts of aldolase were extracted with electrolytes from homogenates of muscles, which lost irreversibly their excitability, and of intact muscles. The actomyosin isolated from muscles displayed aldolase activity not removed under reprecipitation. The aldolase activity of actomyosin, the increase in sorption activity of proteins due to their conformational changes, and the decrease in excitability of aldolase isolated from homogenates of altered muscles by urea doses inducing denaturation of actomyosin and aldolase, all this may suggest that the action of injured agents on muscle stimulates the ability of aldolase and actomyosin to interact. The ratio of free and bound forms of aldolase differs in the intact and in the altered muscle cell.