title: Cleavage of cartilage proteoglycan between G1 and G2 domains by stromelysins.
abstract: Normal and pathological turnover of proteoglycans in articular cartilage involves its cleavage close to the N-terminal G1 domain responsible for aggregation. A fragment containing G1 and G2 N-terminal domains of pig cartilage proteoglycans was therefore used as a substrate to investigate its degradation by the metalloproteinase stromelysin and related recombinant stromelysin enzymes. The stromelysins produced an apparent single cleavage yielding a G1 fragment of 56 kDa and a G2 fragment of 110 kDa. Rabbit bone stromelysin was much more active against the G1-G2 fragment and against proteoglycan aggregates than recombinant human stromelysin-1 and stromelysin-2. All metalloproteinase preparations were active against proteoglycan and the G1-G2 fragment at acid (pH 5.5) and neutral pH (7.4). N-terminal sequencing of the G2 fragment derived from the action of recombinant human stromelysin-1 revealed that cleavage between G1 and G2 occurred at the N-terminal end of the interglobular domain, close to the last cysteine in G1. The specific cleavage site was between an asparagine and a pair of phenylalanine residues, where the asparagine corresponds to residue 341 in human and rat mature core protein sequence.
authors.affiliation: University of Melbourne, Department of Medicine, Royal Melbourne Hospital, Parkville, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Fosang
authors.forename: P J
authors.initials: PJ
authors.lastname: Neame
authors.forename: T E
authors.initials: TE
authors.lastname: Hardingham
authors.forename: G
authors.initials: G
authors.lastname: Murphy
authors.forename: J A
authors.initials: JA
authors.lastname: Hamilton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D002356:Cartilage / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006868:Hydrolysis; D053506:Matrix Metalloproteinase 10; D019278:Matrix Metalloproteinase 3; D008666:Metalloendopeptidases / Q000378:metabolism; D008969:Molecular Sequence Data; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013552:Swine
chemical_list: D011509:Proteoglycans; D011994:Recombinant Proteins; D008666:Metalloendopeptidases; D019278:Matrix Metalloproteinase 3; D053506:Matrix Metalloproteinase 10