Interactions of human matrix metalloproteinase 7 (matrilysin) with the inhibitors thiorphan and R-94138.
The effects of the metalloproteinase inhibitors thiorphan and R-94138 on the matrilysin-catalyzed hydrolysis of (7-methoxycoumarin-4-yl)acetyl-L-Pro-L-Leu-Gly-L-Leu-[N(3)-(2,4-dinitrophenyl)-L-2,3-diamino-propionyl]-L-Ala-L-Arg-NH(2) [MOCAc-PLGL(Dpa)AR] were examined. The inhibitor constants (K(i)) of thiorphan and R-94138 for matrilysin at pH 7.5, 25 degrees C were determined to be 11.2 and 7.65 microM, respectively. From the temperature dependence of the K(i) values at pH 7.5, the standard enthalpy change (Delta H degrees ') values for the binding of matrilysin with thiorphan and R-94138 were determined to be -(18.2 +/- 0.9) and (1.65 +/- 1.07) kJ x mol(-1), respectively. The binding of matrilysin to thiorphan is exothermic and the free energy change in the complex formation depends mainly on the change in enthalpy, while the binding to R-94138 is endothermic and typically entropy-driven. Hydrophobic interactions are suggested to contribute significantly to the binding of matrilysin to R-94138 as well as to the substrate. The pH dependence of the K(i) value suggests that at least two ionizing groups with pK(a) values of 4.5 and 9.1--9.3 are involved in the binding. The matrilysin activity is regulated by ionizing groups with pK(a) values of 4.3 and 9.6. Both inhibition and hydrolysis are suggested to be controlled by the same residues in matrilysin, most likely Glu 198 and Tyr 219, respectively.
Oneda
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H
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Inouye
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K
D000081:Acetamides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D015195:Drug Design; D004795:Enzyme Stability; D006020:Glycopeptides / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006877:Hydroxamic Acids / Q000494:pharmacology; D007700:Kinetics; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D055672:Static Electricity; D013329:Structure-Activity Relationship; D013696:Temperature; D013816:Thermodynamics; D015244:Thiorphan / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
D000081:Acetamides; D006020:Glycopeptides; D006877:Hydroxamic Acids; D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors; C117981:R 94138; C048727:zincov; D015244:Thiorphan; D020783:Matrix Metalloproteinase 7; C008890:phosphoramidon