A SIMPLE PROCEDURE FOR THE PURIFICATION OF STAPHYLOCOCCAL α-TOXIN

Abstract

Staphylococcal .alpha.-toxin was produced in a fluid medium based on acid hydrolyzed casein using strain Wood 46. .alpha.-Toxin and several other proteins were precipitated from bacteria-free culture supernatants by heating at 60.degree. C for 20 min. The process was influenced by the pH of the solution. The toxin was completely inactivated and the precipitate contained a number of proteins if the pH of the solution was adjusted to 4.0-5.0. Heat precipitation of solutions having a pH of 6.0-7.0 resulted in a partial inactivation of .alpha.-toxin. The precipitates at this pH contained less of the additional proteins and had higher relative amounts of .alpha.-toxin than precipitates formed at a lower pH. The precipitate was dissolved in 8 M urea with the resultant activation of the hemolysin. Pure .alpha.-toxin with a MW of 39,000 was obtained by electrophoresis in 8 M urea at pH 8.6 in ordinary tubes for polyacrylamide electrophoresis. The separation time was 45 min. The minor component of .alpha.-toxin with a pI [isoelectric point] of 7.4 could be demonstrated by the same method. A non-hemolytic protein with a MW of 27,500 which existed in at least 2 charged forms, had an antigenic relationship to the toxin with a MW of 39,000.