title: A distinct thimet peptidase from rat liver mitochondria.
abstract: Thimet peptidase has been purified from rat liver mitochondria and found to share the characteristics of a thiol-dependent metallo-endopeptidase previously described for an enzyme in the cytosolic fraction from rat testis: inhibition by EDTA, reactivation by Zn2+, requirement of dithiothreitol for maximal and stable activity, and inhibition by N-ethylmaleimide. The Ki for inhibition by N-[1-(RS)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoic acid is 2.6 microM, 100-fold higher than the value for the cytosolic form. The mitochondrial form is not inhibited by antisera against the cytosolic form, and the two forms of the enzyme show quantitative differences in substrate specificity. The name thimet peptidase II is suggested for the enzyme from rat mitochondria.
authors.affiliation: Department of Biochemistry, Strangeways Research Laboratory, Cambridge, England.
authors.forename: U
authors.initials: U
authors.lastname: Tisljar
authors.forename: A J
authors.initials: AJ
authors.lastname: Barrett
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008666:Metalloendopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D011480:Protease Inhibitors; D008666:Metalloendopeptidases; C022510:thimet oligopeptidase