Studies on Haemolysins from Staphylococcus aureus by the Method of Isoelectric Focusing

Abstract

Publisher Summary This chapter describes studies on hemolysins from Staphylococcus aureus by the method of isoelectric focusing. Staphylococcus aureus produces at least three extracellular hemolytic proteins with different modes of action; α-toxin, or α-hemolysin, is probably the most extensively studied of all the staphylococcal exoproteins. In contrast with α- and β-hemolysins, the δ-lysin is lytic for erythrocytes of a variety of species. Attempts have been made to purify this toxin. In a study, δ-lysin was adsorbed on CM-cellulose equilibrated with 0.05 M phosphate buffer (pH 6.5). Elution was performed stepwise by increasing the concentration of NaCl which yielded 70% of the totally adsorbed δ-lysin. Only a small amount of the α-toxin was adsorbed. Thus, a great similarity in the isoelectric points does not exclude the possibilities of obtaining a separation on an ion exchanger. This is probably because of a difference in the surface charge, while the net charge of the proteins might be very similar. The isoelectric focusing of a prepurified δ-lysin yielded one peak of activity