title: Proteases of the nematode Caenorhabditis elegans.
abstract: Crude homogenates of the soil nematode Caenorhabditis elegans exhibit strong proteolytic activity at acid pH. Several kinds of enzyme account for much of this activity: cathepsin D, a carboxyl protease which is inhibited by pepstatin and optimally active toward hemoglobin at pH 3; at least two isoelectrically distinct thiol proteases (cathepsins Ce1 and Ce2) which are inhibited by leupeptin and optimally active toward Z-Phe-Arg-7-amino-4-methylcoumarin amide at pH 5; and a thiol-independent leupeptin-insensitive protease (cathepsin Ce3) with optimal activity toward casein at pH 5.5. Cathepsin D is quantitatively most significant for digestion of macromolecular substrates in vitro, since proteolysis is inhibited greater than 95% by pepstatin. Cathepsin D and the leupeptin-sensitive proteases act synergistically, but the relative contribution of the leupeptin-sensitive proteases depends upon the protein substrate.
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260.
authors.forename: G J
authors.initials: GJ
authors.lastname: Sarkis
authors.forename: M R
authors.initials: MR
authors.lastname: Kurpiewski
authors.forename: J D
authors.initials: JD
authors.lastname: Ashcom
authors.forename: L
authors.initials: L
authors.lastname: Jen-Jacobson
authors.forename: L A
authors.initials: LA
authors.lastname: Jacobson
mesh_terms: D000818:Animals; D002107:Caenorhabditis / Q000201:enzymology*; D002403:Cathepsins / Q000037:antagonists & inhibitors; D007700:Kinetics; D010447:Peptide Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D011480:Protease Inhibitors; D002403:Cathepsins; D010447:Peptide Hydrolases