title: Kinetic analysis of matrix metalloproteinase activity using fluorogenic triple-helical substrates.
abstract: Matrix metalloproteinase (MMP) family members are involved in the physiological remodeling of tissues and embryonic development as well as pathological destruction of extracellular matrix components. To study the mechanisms of MMP action on collagenous substrates, we have constructed homotrimeric, fluorogenic triple-helical peptide (THP) models of the MMP-1 cleavage site in type II collagen. The substrates were designed to incorporate the fluorophore/quencher pair of (7-methoxycoumarin-4-yl)acetyl (Mca) and N-2,4-dinitrophenyl (Dnp) in the P(5) and P(5)' positions, respectively. In addition, Arg was incorporated in the P(2)' and P(8)' positions to enhance enzyme activity and improve substrate solubility. The desired sequences were Gly-Pro-Lys(Mca)-Gly-Pro-Gln-Gly approximately Leu-Arg-Gly-Gln-Lys(Dnp)-Gly-Ile/Val-Arg. Two fluorogenic substrates were prepared, one using a covalent branching protocol (fTHP-1) and one using a peptide self-assembly approach (fTHP-3). An analogous single-stranded substrate (fSSP-3) was also synthesized. Both THPs were hydrolyzed by MMP-1 at the Gly approximately Leu bond, analogous to the bond cleaved in the native collagen. The individual kinetic parameters for MMP-1 hydrolysis of fTHP-3 were k(cat) = 0.080 s(-1) and K(M) = 61.2 microM. Subsequent investigations showed fTHP-3 hydrolysis by MMP-2, MMP-3, MMP-13, a C-terminal domain-deleted MMP-1 [MMP-1(Delta(243-450))], and a C-terminal domain-deleted MMP-3 [MMP-3(Delta(248-460))]. The order of k(cat)/K(M) values was MMP-13 > MMP-1 approximately MMP-1(Delta(243-450)) approximately MMP-2 >> MMP-3 approximately MMP-3(Delta(248-460)). Studies on the effect of temperature on fTHP-3 and fSSP-3 hydrolysis by MMP-1 showed that the activation energies between these two substrates differed by 3.4-fold, similar to the difference in activation energies for MMP-1 hydrolysis of type I collagen and gelatin. This indicates that fluorogenic triple-helical substrates mimic the behavior of the native collagen substrate and may be useful for the investigation of collagenase triple-helical activity.
authors.affiliation: Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431-0991, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Lauer-Fields
authors.forename: T
authors.initials: T
authors.lastname: Broder
authors.forename: T
authors.initials: T
authors.lastname: Sritharan
authors.forename: L
authors.initials: L
authors.lastname: Chung
authors.forename: H
authors.initials: H
authors.lastname: Nagase
authors.forename: G B
authors.initials: GB
authors.lastname: Fields
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D053509:Matrix Metalloproteinase 13; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011817:Rabbits; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D005456:Fluorescent Dyes; D010446:Peptide Fragments; D003094:Collagen; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1