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

Abstract

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.