Biochemical properties of purified cathepsin B from Schistosoma mansoni.
A previously described "major acidic proteinase" of adult Schistosoma mansoni, believed to play a key role in the parasite's metabolism, has been identified as a cathepsin B (Sm31). Purified Sm cathepsin B was not recognized by anti-Sm32 or anti-cathepsin L antibodies. The enzyme hydrolyzes the synthetic protease substrates Z-Arg-Arg-AMC and Z-Phe-Arg-AMC as well as protein substrates. Its pH optimum is 3.0 with serum albumin, 4.0-5.0 with globin and 5.5-6.0 with the synthetic substrates. The enzyme was inactivated by cysteine proteinase inhibitors. Its activity against protein substrates would support the hypothesis that it plays a role in schistosome nutrition.
Ghoneim
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Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Rome, Italy.
Klinkert
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D000595:Amino Acid Sequence; D000818:Animals; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D003374:Coumarins; D004151:Dipeptides; D005914:Globins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007120:Immunochemistry; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology; D012550:Schistosoma mansoni / Q000201:enzymology*; D013379:Substrate Specificity
D003374:Coumarins; D004151:Dipeptides; D009842:Oligopeptides; C021159:benzyloxycarbonyl-phenylalanylarginine-4-methylcoumaryl-7-amide; C069012:benzyloxycarbonylarginyl-arginine 4-methylcoumarin-7-ylamide; D005914:Globins; D002401:Cathepsin B