Trypsin-mediated activation of the alpha-haemolysin of Staphylococcus aureus

Alpha protoxin of Staphylococcus aureus "Wood 46" was activated by trypsin which had been coupled to carboxymethylcellulose, as indicated by the toxin's ability to hydrolyse tosyl-arginine methylester (TAME). A Lineweaver-Burk plot of the degradation of TAME by toxin and trypsin showed that toxin had a greater affinity for the substrate than had trypsin. N-terminal amino-acid analyses of activated toxin suggested that leucine or isoleucine is the N-terminus, in contrast to protoxin, the N-terminus of which is histidine.