PURIFICATION OF STAPHYLOCOCCAL β-LYSIN

A method is described by which staphylococcal β-lysin may be purified some 250 times, with overall yields of 50–60%. The procedure consists of three steps by which impurities are removed and the lysin solution concentrated. Firstly, zinc acetate is added to ice-cold, dialyzed solutions of crude lysin followed by cold ethanol to precipitate the zinc–lysin complex. Zinc is removed by dissolving the complex in water plus chelating agent, followed by dialysis at low temperature. Secondly, the lysin is reprecipitated by formation of the water-insoluble zinc–mercuric–lysin complex and again resolved as after the first precipitation. Finally, reprecipitated lysin is further purified by chromatography, employing columns of hydroxylapatite. The final preparation was free of detectable quantities of other known hemolysins and of coagulase and phosphatase.