The purification and properties of streptolysin S.

Considerable purification of streptolysin S has been achieved by fractionation of crude bacterial filtrates with methanol, under controlled conditions of pH, ionic strength, and temperature. The final material (P III) consisted of two electrophoretic components. The purified material was employed for kinetic studies, the results of which were confirmed with hemolysin isolated electrophoretically from P III. The heat of activation (temperature characteristic) of streptolysin S was found to be 17,900 calories per mole. Time dilution curves of the hemolysin were found to be sigmoid. The influence of certain ions and lipids on the course of hemolysis was investigated. The significance of the prolonged lag period and of the deviation in the behavior of streptolysin S from Ponder's equation has been discussed.