title: Differential effects of oleic acid, sodium dodecyl sulfate, and protease inhibitors on the endopeptidase activities of the lobster multicatalytic proteinase.
abstract: 1. Lobster muscles contain a latent multicatalytic proteinase; heating at 60 degrees C for 1-2 min converts the latent form to a heat-activated form with enhanced proteolytic activity. Both forms have three endopeptidase activities, which are classified as the trypsin-like, chymotrypsin-like, and peptidylglutamylpeptide bond hydrolyzing activities. 2. Sulfhydryl reagents (mersalyl acid, N-ethylmaleimide, hemin, iodoacetamide, and p-chloromercurisulfonic acid), benzamidine, and chloromethyl ketones inhibited all three activities of the heat-activated form. Leupeptin and antipain inhibited only the trypsin-like activity, while the chymotrypsin-like activity was the most sensitive to diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, aprotinin, and soybean trypsin inhibitor. Pepstatin and L-trans-epoxysuccinylpeptides had little effect on the peptidase activities. 3. Sodium dodecyl sulfate and oleic acid preferentially activated the peptidylglutamyl-peptide hydrolyzing activity of the latent form, whereas N-ethylmaleimide stimulated both the trypsin-like and peptidylglutamyl-peptide hydrolases. These results suggest that the lobster enzyme is an atypical serine proteinase.
authors.affiliation: Department of Biology, Colorado State University, Fort Collins 80523.
authors.forename: J J
authors.initials: JJ
authors.lastname: Clark
authors.forename: T L
authors.initials: TL
authors.lastname: Ilgen
authors.forename: M F
authors.initials: MF
authors.lastname: Haire
authors.forename: D L
authors.initials: DL
authors.lastname: Mykles
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism*; D008121:Nephropidae; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology*; D009842:Oligopeptides; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D013379:Substrate Specificity
chemical_list: D009097:Multienzyme Complexes; D009829:Oleic Acids; D009842:Oligopeptides; D011480:Protease Inhibitors; D019301:Oleic Acid; D012967:Sodium Dodecyl Sulfate; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex