title: Characterization of the monomeric and dimeric forms of latent and active matrix metalloproteinase-9. Differential rates for activation by stromelysin 1.
abstract: Matrix metalloproteinase-9 (MMP-9) is a member of the MMP family that has been associated with degradation of the extracellular matrix in normal and pathological conditions. A unique characteristic of MMP-9 is its ability to exist in a monomeric and a disulfide-bonded dimeric form. However, there exists a paucity of information on the properties of the latent (pro-MMP-9) and active MMP-9 dimer. Here we report the purification to homogeneity of the monomer and dimer forms of pro-MMP-9 and the characterization of their biochemical properties and interactions with tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Gel filtration and surface plasmon resonance analyses demonstrated that the pro-MMP-9 monomeric and dimeric forms bind TIMP-1 with similar affinities. In contrast, TIMP-2 binds only to the active forms. After activation, the two enzyme forms exhibited equal catalytic competence in the turnover of a synthetic peptide substrate with comparable kinetic parameters for the onset of inhibition with TIMPs and for dissociation of the inhibited complexes. Kinetic analyses of the activation of monomeric and dimeric pro-MMP-9 by stromelysin 1 revealed K(m) values in the nanomolar range and relative low k(cat) values (1.9 x 10(-3) and 4.1 x 10(-4) s(-1), for the monomer and dimer, respectively) consistent with a faster rate (1 order of magnitude) of activation of the monomeric form by stromelysin 1. This suggests that the rate-limiting event in the activation of pro-MMP-9 may be a requisite slow unfolding of pro-MMP-9 near the site of the hydrolytic cleavage by stromelysin 1.
authors.affiliation: Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Olson
authors.forename: M M
authors.initials: MM
authors.lastname: Bernardo
authors.forename: M
authors.initials: M
authors.lastname: Pietila
authors.forename: D C
authors.initials: DC
authors.lastname: Gervasi
authors.forename: M
authors.initials: M
authors.lastname: Toth
authors.forename: L P
authors.initials: LP
authors.lastname: Kotra
authors.forename: I
authors.initials: I
authors.lastname: Massova
authors.forename: S
authors.initials: S
authors.lastname: Mobashery
authors.forename: R
authors.initials: R
authors.lastname: Fridman
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D019281:Dimerization; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D020349:Surface Plasmon Resonance; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; D011994:Recombinant Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9