PURIFICATION OF STAPHYLOCOCCAL-ALPHA-LYSIN

Abstract

A method for the purification and concentration of staphylococcal-α-lysin is described. Zinc–lysin complex, formed by addition of zinc–acetate to dialyzed, crude solutions of lysin, is precipitated with ethanol at low temperature. All but traces of zinc, together with some inactive material is removed from the precipitate by extraction with ethanol–water mixtures under conditions of pH and ethanol content which maintain the lysin in precipitated form. Further purification of the active material is achieved by chromatography employing columns composed of hydroxylapatite. The purified lysin is 250 times as active as the crude starting material in terms of hemolytic units per milligram of nitrogen.Rabbit erythrocytes are susceptible whereas human erythrocytes are resistant to the hemolytic activity of purified α-lysin. It is dermonecrotic when injected intradermally into rabbits and lethal when introduced intraperitoneally into mice in quantities of 20 hemolytic units per 25 g mouse.