Studies on the preparation and isoelectric point of staphylococcal α-haemolysin

Abstract

Attempts to purify staphylococcal [alpha] -hemolysin by means of ammonium sulphate, ethanol and Cellosolve failed to give preparations of very high purity or activity. Ammonium sulphate was relatively harmless but limited in its powers of fractionation. Cellosolve, in contrast with ethanol, effected a further step in purification. Comparison of the ratios of the lethal to hemolytic activities of the preparations indicates a differential denaturation of the active factors. Support is given for the view that there is a multiplicity of active factors. The isoelectric point of the hemolytic factor was determined by an electrophoretic-fractionation method and found to be at pH 6:4.