title: Purification and characterization of intracellular proteases of Clostridium perfringens type A.
abstract: Five intracellular proteases from sporulating cells of Clostridium perfringens type A were identified and three could be separated by DEAE-Sephacel. Two, I-A and I-B, had caseinolytic activity and one, I-C, was only active on N-benzoyl-DL-arginine-p-nitroanilide. I-A and I-B could each be further separated by Sephacryl S-300 into I-A-1 and I-A-2 and I-B-1 and I-B-2, respectively. I-A-1, a chymotrypsin-like enzyme, was the major intracellular protease, constituting 74% of the intracellular caseinolytic activity. In addition to cytoplasmic proteases both trypsin and chymotrypsin-like enzyme activity was associated with the membrane fraction. I-A-1 had a molecular weight of 330,000, with subunits of 120,000 and 138,000. I-A-1 cleaved a 1200 molecular weight peptide from C. perfringens enterotoxin. Early sporulating cell extracts of C. perfringens contained three presumptive enterotoxin precursors, which disappeared following treatment with I-A. Such cells also contained at least 10 spore coat related proteins, only one (51,500 molecular weight) of which was sensitive to I-A-1. The results indicate a possible role for the major intracellular protease in the processing of C. perfringens enterotoxin and a less important role, if any, in spore coat formation.
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst 01003.
authors.forename: K B
authors.initials: KB
authors.lastname: Park
authors.forename: R G
authors.initials: RG
authors.lastname: Labbé
mesh_terms: D003016:Clostridium perfringens / Q000201:enzymology*; D010450:Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004768:Enterotoxins; D007424:Intracellular Fluid / Q000201:enzymology; D008970:Molecular Weight; D013171:Spores, Bacterial / Q000201:enzymology; D013379:Substrate Specificity
chemical_list: D004768:Enterotoxins; D010450:Endopeptidases