title: Purification and properties of different isoforms of bovine cathepsin B.
abstract: A rapid purification procedure is described for cathepsin B from bovine liver. After preparation of crude lysosomal extracts, the method only involves DEAE Zeta-Prep-Disk chromatography, gel filtration, and fast protein liquid chromatography on Mono-S column. Two active peaks (P1 and P2) of cathepsin B were distinguished. Both presented uncleaved (relative mass (Mr) 30,000) and cleaved (Mr 25,000 + Mr 5000) chains, but different isoforms as revealed by isoelectrofocusing. These two different populations of cathepsin B isoforms nevertheless exhibited similar enzymatic properties. Km and kcat were 114 microM and 52 s-1, and 125 microM and 75 s-1, for hydrolysis of Z-Arg-Arg-NMec by P1 and P2, respectively. Both were rapidly inhibited by low concentrations of E-64 or leupeptin, but were unaffected by cathepsin-L-specific inhibitor Z-Phe-Phe-CHN2.
authors.affiliation: Unité de recherche sur les protéases, Institut national de la recherche agronomique SRV, Ceyrat, France.
authors.forename: C
authors.initials: C
authors.lastname: Deval
authors.forename: D
authors.initials: D
authors.lastname: Bechet
authors.forename: A
authors.initials: A
authors.lastname: Obled
authors.forename: M
authors.initials: M
authors.lastname: Ferrara
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D002417:Cattle; D002850:Chromatography, Gel; D002853:Chromatography, Liquid; D007525:Isoelectric Focusing; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology
chemical_list: D002401:Cathepsin B