title: Cathepsin B and L activities in isolated osteoclasts.
abstract: Cathepsin B and L activities were examined with chicken osteoclasts isolated by sequential filtration and inhibitors were added to disaggregated rat osteoclasts on cortical bovine bone. Z-Phe-Phe-CHN2, a selective inhibitor of cathepsin L, at 1, 5, and 10 microM, inhibited bone resorption by rat osteoclasts 50, 85, and 100 per cent and, in chicken osteoclasts, cathepsin L activity was comparably inhibited. Cathepsin L in avian osteoclasts was also 25-fold higher than cathepsin B. Chicken osteoclasts treated with Z-Phe-Ala-CHN2, a generalized cysteine proteinase inhibitor, had both cathepsins inhibited to the same extent. Cathepsin L may play a key role in resorption.
authors.affiliation: Department of Oral Medicine and Pathology, New York University College of Dentistry, New York 10010.
authors.forename: B R
authors.initials: BR
authors.lastname: Rifkin
authors.forename: A T
authors.initials: AT
authors.lastname: Vernillo
authors.forename: A P
authors.initials: AP
authors.lastname: Kleckner
authors.forename: J M
authors.initials: JM
authors.lastname: Auszmann
authors.forename: L R
authors.initials: LR
authors.lastname: Rosenberg
authors.forename: M
authors.initials: M
authors.lastname: Zimmerman
mesh_terms: D000818:Animals; D001862:Bone Resorption; D002401:Cathepsin B / Q000378:metabolism*; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D002478:Cells, Cultured; D002645:Chickens; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003978:Diazomethane / Q000031:analogs & derivatives / Q000494:pharmacology; D010450:Endopeptidases; D007700:Kinetics; D010010:Osteoclasts / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D013379:Substrate Specificity
chemical_list: D015853:Cysteine Proteinase Inhibitors; C024918:benzyloxycarbonylphenylalanylalanine diazomethyl ketone; D003978:Diazomethane; C031947:benzyloxycarbonylphenylalanylphenylalanine diazomethyl ketone; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534280:Ctsl protein, rat