title: The bovine lens neutral proteinase comprises a family of cysteine-dependent proteolytic activities.
abstract: Inhibitor studies with peptide substrates demonstrate that bovine lens neutral proteinase comprises three distinct activities. Diisopropylfluorophosphate distinguishes the activity hydrolyzing carbobenzoxy-Gly-Gly-Leu-p-nitroanilide (inhibited) from that hydrolyzing carbobenzoxy-Leu-Leu-Glu-2-naphthylamide (not inhibited). Leupeptin inhibits hydrolysis of the substrate carbobenzoxy-Leu-Leu-Arg-2-naphthylamide, but not hydrolysis of carbobenzoxy-Gly-Gly-Leu-p-nitroanilide or carbobenzoxy-Leu-Leu-Glu-2-naphthylamide, demonstrating the presence of the third activity. Inhibition of the three activities by thiol reagents suggests that each activity may be dependent on an active-site cysteine residue.
mesh_terms: D000818:Animals; D002417:Cattle; D003545:Cysteine / Q000502:physiology*; D010450:Endopeptidases / Q000378:metabolism*; D006868:Hydrolysis; D007908:Lens, Crystalline / Q000201:enzymology*; D007976:Leupeptins / Q000494:pharmacology; D015260:Neprilysin; D009578:Nitrobenzenes / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism
chemical_list: D007976:Leupeptins; D009578:Nitrobenzenes; D009842:Oligopeptides; D011480:Protease Inhibitors; C051008:N-carbobenzoxyleucyl-leucyl-arginine-2-naphthylamide; D010450:Endopeptidases; D010447:Peptide Hydrolases; D014357:Trypsin; D015260:Neprilysin; C032854:leupeptin; D003545:Cysteine; C005805:quintozene