Complement-inactivating proteinase(s) from Clostridium histolyticum.
A proteinase fraction inhibiting the hemolytic activity of guinea pig complement was obtained from supernatant fluids of Clostridium histolyticum cultures and purified 150- to 350-fold by ammonium sulfate precipitation, Sephadex G-75 gel filtration, and diethylaminoethyl cellulose chromatography. An assay was developed based on the inactivation of hemolytic complement. Partially purified anticomplementary preparations were active against casein and were capable of "solubilizing" Escherichia coli endotoxin. Two components were found by differential heat inactivation, with complement and casein as substrates, but only one of these components was active against endotoxin. The more heat-stable activity, showing 50% inactivation at about 47 C, was characterized as to pH and ionic strength optima and sensitivity to reagents such as cysteine, beta-mercaptoethanol, ethylenediaminetetraacetate, and heavy metals.