Proteolytic degradation of staphylococcal alpha-toxin

Staphylococcal alpha-toxin of mol.wt. 39,000 was degraded at an alkaline pH by staphylococcal extracellular proteases resulting in the formation of three relatively stable intermediates with mol.wt. 27,500, 23,500 and 12,000. The intermediate with mol.wt. 27,500 which existed in two charged forms, was isolated by column chromatography and found to be non-haemolytic. Furthermore, it could be obtained by proteolysis of alpha-toxin (mol.wt. 39,000) with chymotrypsin in low concentrations. This intermediate was further degraded by trypsin to the protein with mol.wt. 23,500 and 12,000.