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Publications (8)29.48 Total impact

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    ABSTRACT: Carboxyalkyl peptides containing a biphenylylethyl group at the P1' position were found to be potent inhibitors of stromelysin-1 (MMP-3) and gelatinase A (MMP-2), in the range of 10-50 nM, but poor inhibitors of collagenase (MMP-1). Combination of a biphenylylethyl moiety at P1', a tert-butyl group at P2', and a methyl group at P3' produced orally bioavailable inhibitors as measured by an in vivo model of MMP-3 degradation of radiolabeled transferrin in the mouse pleural cavity. The X-ray structure of a complex of a P1-biphenyl inhibitor and the catalytic domain of MMP-3 is described. Inhibitors that contained halogenated biphenylylethyl residues at P1' proved to be superior in terms of enzyme potency and oral activity with 2(R)-[2-(4'-fluoro-4-biphenylyl)ethyl]-4(S)-n-butyl-1,5-pentane dioic acid 1-(alpha(S)-tert-butylglycine methylamide) amide (L-758,354, 26) having a Ki of 10 nM against MMP-3 and an ED50 of 11 mg/kg po in the mouse pleural cavity assay. This compound was evaluated in acute (MMP-3 and IL-1 beta injection in the rabbit) and chronic (rat adjuvant-induced arthritis and mouse collagen-induced arthritis) models of cartilage destruction but showed activity only in the MMP-3 injection model (ED50 = 6 mg/kg iv).
    Journal of Medicinal Chemistry 04/1997; 40(6):1026-40. · 5.61 Impact Factor
  • Bioorganic & Medicinal Chemistry Letters 01/1996; 6(3). · 2.34 Impact Factor
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    ABSTRACT: Nitric oxide synthase (EC 1.14.23) substrate analog inhibitors NG-monomethyl-L-Arg, NG-nitro-L-Arg, NG-nitro-L-Arg methyl ester, and aminoguanidine were examined as potential inhibitors of rat liver arginase (EC 3.5.3.1). NG-nitro-L-Arg was found to inhibit arginase catalyzed conversion of L-Arg to L-Orn at pH 7.5 with an IC50 = 27.2 +/- 4.3 mM, compared to L-Val and L-Lys with IC50 values of 6.2 +/- 0.4 mM and 31.3 +/- 2.7 mM, respectively. Inhibition was stereospecific for the L-amino acid, not NG-nitro-D-Arg, and required a free alpha-carboxyl group. NG-nitro-L-Arg was not a substrate for rat liver arginase. These results suggest that arginase inhibition should also be evaluated when studying the effects of NOS substrate analog inhibitors in vivo.
    Biochemical and Biophysical Research Communications 01/1994; 197(2):523-8. · 2.41 Impact Factor
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    ABSTRACT: An extensive study of the requirements for effective binding of N-carboxyalkyl peptides to human stromelysin, collagenase, and to a lesser extent, gelatinase A has been investigated. These efforts afforded inhibitors generally in the 100-400 nM range for these matrix metalloproteinases. The most significant increase in potency was obtained with the introduction of a beta-phenylethyl group at the P1' position, suggesting a small hydrophobic channel into the S1' subsite of stromelysin. One particular compound, N-[1(R)-carboxyethyl]-alpha(S)-(2-phenylethyl)glycyl-L-leucine,N- phenylamide (79a), is relatively selective for rabbit stromelysin with a K(i) = 6.5 nM and may prove useful for elucidating the role of endogenously-produced stromelysin in lapine models of tissue degradation.
    Journal of Medicinal Chemistry 01/1994; 36(26):4293-301. · 5.61 Impact Factor
  • L Niedzwiecki, J Teahan, R K Harrison, R L Stein
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    ABSTRACT: To probe the specificity of the metalloendoproteinase stromelysin toward peptide substrates, we determined kc/Km values for the stromelysin-catalyzed hydrolyses of peptides whose design was based loosely on the structure of a known SLN substrate, substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2, hydrolysis at Gln-Phe, kc/Km = 1700 M-1 s-1). Several noteworthy points emerge from this study: (i) Catalytic efficiency is dependent on peptide chain length with N-terminal truncation of substance P resulting in more pronounced rate-constant reductions than C-terminal truncation. These results suggest the existence of an extended active site for stromelysin. (ii) Preferences at positions P3, P2, P1, P1', and P2' are for the hydrophobic amino acids Pro, Leu, Ala, Nva, and Trp, respectively. (iii) Investigation of specificity at P3' supports our earlier hypothesis that SLN has a requirement for a hydrogen-bond donor at this position in its substrates. Based on these observations, we designed and had synthesized the fluorogenic substrate N-(2,4-dinitrophenyl)Arg-Pro-Lys-Pro-Leu-Ala-Nva-TrpNH2, whose stromelysin-catalyzed hydrolysis can be monitored continuously (kc/Km = 45,000 M-1 s-1).
    Biochemistry 01/1993; 31(50):12618-23. · 3.38 Impact Factor
  • R K Harrison, B Chang, L Niedzwiecki, R L Stein
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    ABSTRACT: To probe the mechanism of stromelysin (SLN)-catalyzed peptide hydrolysis, we determined the pH dependence of kc/Km and solvent deuterium isotope effects on kc and kc/Km. pH dependencies of kc/Km were determined for the SLN-catalyzed hydrolysis of three peptides: Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Nle-NH2,Arg-Pro-Ala-Pro-Gln-Gln- Phe-Phe - Gly-Leu-NleNH2, and N-acetyl-Arg-Pro-Ala-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Nle-NH2 (cleavage at Gln-Phe bond). The pH dependencies are all bell-shaped with shoulders that extend from pH 7.5 to 8.5. The existence of a shoulder indicates that the reaction mechanism involves at least two routes to products. These curves are governed by three proton ionizations with pKa values of 5.4, 6.1, and 9.5. The solvent isotope effect measurements provided the following values: D(kc/Km) = 0.80 +/- 0.05 and D(kc) = 1.58 +/- 0.05. That D(kc/Km) and D(kc) are different suggests that the rate-limiting transition states for the processes governed by kc/Km and kc cannot be the same. We use these results, together with analogy to thermolysin catalysis, to develop a mechanism for SLN catalysis.
    Biochemistry 12/1992; 31(44):10757-62. · 3.38 Impact Factor
  • R K Harrison, R L Stein
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    ABSTRACT: Substrate specificities, as reflected in kc/Km, were determined for the peptidyl prolyl cis-trans isomerase activities of cyclophilin and the FK-506 binding protein (FKBP). The substrates investigated were peptides of the general structure Suc-Ala-Xaa-Pro-Phe-p-nitroanilide, where Xaa = Gly, Ala, Val, Leu, Phe, His, Lys, on Glu. While kc/Km for cyclophilin-catalyzed isomerization shows little dependence on Xaa, kc/Km values for FKBP-catalyzed isomerization display a marked dependence on Xaa and vary over 3 orders of magnitude. An important outcome of this work is the discovery that Suc-Ala-Leu-Pro-Phe-pNA is a reactive substrate for FKBP (kc/Km = 640,000 M-1 s-1). This substrate can be used with FKBP concentrations that are low enough to allow, for the first time, accurate determinations of Ki values for tight-binding inhibitors of FKBP. Using this new assay, we found that FK-506 inhibits FKBP with Ki = 1.7 +/- 0.6 nM. The results of this work support the hypothesis that cyclophilin and FKBP are members of a family of peptidyl prolyl cis-trans isomerases and that the members of this family possess distinct substrate specificities that allow them to play diverse physiologic roles.
    Biochemistry 05/1990; 29(16):3813-6. · 3.38 Impact Factor
  • R K Harrison, R L Stein
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    ABSTRACT: Cyclophilin, the cytosolic binding protein for the immunosuppressive drug cyclosporin A, has recently been shown to be identical with peptidyl prolyl cis-trans isomerase [Fischer, G., Wittmann-Liebold, B., Lang, K., Kiefhaber, T., & Schmid, F.X. (1989) Nature 337, 476; Takahashi, N., Hayano, T., & Suzuki, M. (1989) Nature 337, 473]. To provide a mechanistic framework for studies of the interaction of cyclophilin with cyclosporin, we investigated the mechanism of the PPI-catalyzed cis to trans isomerization of Suc-Ala-Xaa-cis-Pro-Phe-pNA (Xaa = Ala, Gly). Our mechanistic studies of peptidyl prolyl cis-trans isomerase include the determination of steady-state kinetic parameters, pH and temperature dependencies, and solvent and secondary deuterium isotope effects. The results of these experiments support a mechanism involving catalysis by distortion in which the enzyme uses free energy released from favorable, noncovalent interactions with the substrate to stabilize a transition state that is characterized by partial rotation about the C-N amide bond.
    Biochemistry 02/1990; 29(7):1684-9. · 3.38 Impact Factor