Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The X-ray crystal structure of the trypsin complex formed with N alpha-(2-naphthyl-sulphonyl-glycyl)-DL-p-amidinophenylalanyl-piper idine (NAPAP) was determined with X-ray data to 0.18-nm resolution and crystallographically refined. NAPAP binds into the active site of trypsin in a quite compact form: the p-amidinophenylalanine moiety of the D-stereoisomer binds into the specificity pocket; the glycyl group is hydrogen bonded with Gly216; the naphthyl group stands perpendicular to the indole moiety of Trp215; the piperidine ring is tightly packed between this naphthyl moiety and His57; in consequence the carboxy-terminal amido bond of NAPAP is located in such a way that it is not susceptible to the active-site Ser195. NAPAP and (2R,4R)-4-methyl-1-[N alpha-(3-methyl-1,2,3,4-tetrahydro-8- quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid (MQPA) [Matzusaki, T., Sasaki, C., Okumura, C. & Umeyama (1989) J. Biochem. (Tokyo) 105, 949-952] were transferred in their trypsin-binding conformations to human alpha-thrombin [Bode, W., Mayr, I., Baumann, U., Huber, R., Stone, S. R. & Hofsteenge, J. (1989) EMBO J. 8. 3467 - 3475] and energy minimized. Both synthetic inhibitors fit perfectly into the much more restricted active site of thrombin. The accommodation of the S-aryl moieties in the 'aryl-binding site' and of the piperidine rings in the S2 subsite of thrombin are particularly favorable. The preference of thrombin for distinctly substituted piperidine derivatives and its generally higher (compared with trypsin) affinity for benzamidine and arginine-based inhibitors can be accounted for by these thrombin inhibitor models.
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PMID:Geometry of binding of the benzamidine- and arginine-based inhibitors N alpha-(2-naphthyl-sulphonyl-glycyl)-DL-p-amidinophenylalanyl-pipe ridine (NAPAP) and (2R,4R)-4-methyl-1-[N alpha-(3-methyl-1,2,3,4-tetrahydro-8- quinolinesulphonyl)-L-arginyl]-2-piperidine carboxylic acid (MQPA) to human alpha-thrombin. X-ray crystallographic determination of the NAPAP-trypsin complex and modeling of NAPAP-thrombin and MQPA-thrombin. 222 34

The inhibitory effects of 6-amidino-2-naphthyl-4-guanidinobenzoate X dimethanesulfonate (FUT-175) on the human Hageman factor fragment (HFf), factor Xa, thrombin, plasma kallikrein, and plasmin were studied. FUT-175 inhibited plasma kallikrein most (IC50 = 3.0 X 10(-9) M), followed by HFf (IC50 = 3.3 X 10(-7) M). FUT-175 was found to have an anticoagulant effect in the APTT and PT assay systems of human plasma. The concentration of FUT-175 for twofold increase in the clotting time in the APTT assay system was 5 X 10(-7) M.
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PMID:Inhibitory effect of a new synthetic protease inhibitor (FUT-175) on the coagulation system. 316 8

FUT-175 (6 amidino-2-naphthyl-4-guanidino benzoate-dimethanesulfonate), a new synthetic protease inhibitor, inhibits the enzyme activities of various proteases, such as Clr, C1 esterase, thrombin, kallikrein, plasmin and trypsin. FUT-175 strongly inhibited complement-medicated hemolysis via the classical and alternative pathways. The effects of FUT-175 on various immunological reactions in vivo were studied. The minimal effective dose of FUT-175 in systemic Forssman shock in guinea pigs was 6.25 mg/kg i.p. and 25 mg/kg p.o. In passive Arthus reactions in rats, the effective dose was 25 mg/kg i.p. and 250 mg/kg p.o. FUT-175 also inhibited other immunological reactions, such as passive cutaneous anaphylaxis and delayed hypersensitivity. Furthermore, at a dose of 25 mg/kg i.p. it strongly protected mice from death in endotoxin shock.
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PMID:Inhibition of various immunological reactions in vivo by a new synthetic complement inhibitor. 621 61

p-Guanidinobenzoate derivates were prepared and their inhibitory effects on trypsin, plasmin, pancreatic kallikrein, plasma kallikrein, thrombin, C1r and C1 esterase were examined. Among the various inhibitors tested, 6'-amidino-2-naphthyl-4-guanidinobenzoate dihydrochloride, 4-(beta-amidinoethenyl)phenyl-4-guanidinobenzoate dimethanesulfonate and 4-amidino-2-benzoylphenyl-4-guanidinobenzoate dimethanesulfonate were the most effective inhibitors of trypsin, plasmin, pancreatic kallikrein. plasma kallikrein and thrombin and they strongly inhibited the esterolytic activities of C1r and C1 esterase, and then strongly inhibited complement-mediated hemolysis.
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PMID:New synthetic inhibitors of C1r, C1 esterase, thrombin, plasmin, kallikrein and trypsin. 627 Dec 24

FUT-175, 6-amidino-2-naphthyl p-guanidinobenzoate dimethanesulfonate (nafamstat mesilate), a novel synthetic protease-inhibiting agent, was studied to determine its in vitro effects against various proteases and other enzymes, as well as to determine its in vivo protease inhibitory effects. FUT-175 was found to inhibit, in an intense, specific and reversible way, the enzyme activities of trypsin, C1r, C1s, thrombin, kallikrein and plasmin with IC50 values of the order of 10(-6)-10(-8) M. FUT-175 also inhibited complement-mediated hemolysis, including both classical and alternative pathways, sites of inhibition being on C1r and C1s as evidenced by the intermediate-cell technique. In animal model reactions in which the complement system is known to be involved as pathogenetic factors, e.g., Forssman shock, Forssman cutaneous vasculitis, zymosan-induced paw edema, endotoxin shock and local Shwartzman reaction, FUT-175 was highly effective in that, for example, intravenous dosing at 3 mg/kg could completely protect guinea pigs from the lethal Forssman shock. FUT-175 was also found to be effective in trypsin-induced shock in mice, in lethality due to thrombin-thrombosis in mice and in kinin formation in the inflammatory process in rats.
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PMID:Pharmacological studies of FUT-175, nafamstat mesilate. I. Inhibition of protease activity in in vitro and in vivo experiments. 648 87

Proteolytic action of alpha-thrombin on human thrombin receptor results in cleavage of a portion of the N-terminus, thereby generating a 'tethered ligand' at the newly exposed N-terminus, which then activates the receptor in an intramolecular fashion. Agonist peptides incorporating the amino acid sequence of the newly exposed N-terminal portion of the cleaved receptor cause receptor activation without requiring prior cleavage of the receptor by thrombin. The pentapeptide amide Ser-Phe-Leu-Leu-Arg-NH2, which retains the N-terminal sequence of the 'tethered ligand' of the receptor, has been shown to be the minimum sequence to cause receptor activation. To understand the importance of the side chains of various residues within the pentapeptide amide, we carried out an extensive structure-activity study of the ability of peptides to stimulate gel-filtered platelet aggregation. In this study 106 pentapeptide amides were synthesized, utilizing naturally occurring L-amino acids, unnatural amino acids, D-amino acids and N-methyl amino acids for replacements. At position-1, charged residues (acidic or basic) were not tolerated, and the size and shape of the residue were important. Position-2 tolerated only aromatic residues. Position-3 accommodated various residues. A significant finding of this study was that two very different residues, [3-(2-naphthyl)]-L-alanine and L-arginine, when substituted for leucine residue at position-3, resulted in more active agonists. At position-4 aromatic and aliphatic residues were well tolerated, whereas basic and acidic residues were less tolerated. Position-5 mimicked position-3 in its ability to tolerate a wide range of residues.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:'Tethered ligand' derived pentapeptide agonists of thrombin receptor: a study of side chain requirements for human platelet activation and GTPase stimulation. 778 62

The two crystal structures of thrombin complexed with its most potent natural inhibitor hirudin and with the active-site inhibitor D-Phe-Pro-Arg-CH2Cl [Rydel, T.J. et al., J. Mol. Biol., 221 (1991) 583; Bode, W. et al., EMBO J., 8 (1989) 3467] were used as a basis to design a new inhibitor, combining the high specificity of the polypeptide hirudin with the simpler chemistry of an organic compound. In the new inhibitor, the C-terminal amino acid residues 53-65 of hirudin are linked by a spacer peptide of four glycines to the active-site inhibitor NAPAP (N alpha-(2-naphthyl-sulfonyl-glycyl)-DL-p-amidinophenylalanyl-piperi dine). Energy minimization techniques served as a tool to determine the preferred configuration at the amidinophenylalanine and the modified piperidine moiety of the inhibitor. The predictions are supported by the interaction energies determined for D- and L-NAPAP in complex with thrombin, which are in good agreement with experimentally determined dissociation constants. The conformational flexibility of the linker peptide in the new inhibitors was investigated with molecular dynamics techniques. A correlation between the Pl' position and the interactions of the linker peptide with the protein is suggested. Modifications of the linker peptide are proposed based on the distribution of its main-chain torsion angles in order to enhance its binding to thrombin.
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PMID:Rational design of hirulog-type inhibitors of thrombin. 787 96

The aim of our study was to characterize a model of human prostaglandin endoperoxide synthase-2 (PGHS-2) expression allowing the assessment of pharmacological inhibition in vitro and ex vivo. Heparinized human whole blood samples were incubated with lipopolysaccharide (LPS, 0.1-50 micrograms/ml) for 0 to 24 hr at 37 degrees C. The contribution of platelet PGHS-1 was suppressed by either pretreating the subjects with aspirin (300 mg 48 hr before sampling) or adding aspirin (10 micrograms/ml) in vitro at time 0. PGE2 was measured by radioimmunoassay. LPS induced expression of cyclooxygenase activity in a time- and concentration-dependent fashion. After 24 hr at 10 micrograms/ml LPS, PGE2 production averaged 12.1 +/- 6.2 ng/ml (mean +/- S.D., n = 7). Cyclooxygenase activity increased in parallel with the mass of a monocyte protein doublet analyzed by Western blot using antibodies directed against the carboxyl-terminal portion of human PGHS-2. Dexamethasone (2 microM) inhibited LPS-induced PGE2 production by 96 +/- 4% (mean +/- S.D., n = 3). Four different inhibitors were tested in vitro on the cyclooxygenase activity of LPS-induced monocyte PGH-2 and thrombin-stimulated platelet PGHS-1. IC50 values (microM) for inhibition of PGHS-1 and PGHS-2 were: indomethacin, 0.70 +/- 0.20 vs 0.36 +/- 0.10 (P < .05); S-indobufen, 0.64 +/- 0.22 vs. 14.9 +/- 8 (P < .05), R-indobufen, 38 +/- 18 vs. 230 +/- 68 (P < .01), 6-methoxy-2-naphthyl acetic acid (the active metabolite of nabumetone), 278 +/- 96 vs. 187 +/- 96.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biochemical and pharmacological characterization of the cyclooxygenase activity of human blood prostaglandin endoperoxide synthases. 799 88

Since activated factor X (FXa) is a coagulant enzyme that generates thrombin and participates in both intrinsic and extrinsic coagulation pathways, inhibition of FXa may be more effective than inactivation of thrombin for interrupting blood coagulation. To assess the possible effectiveness of FXa inhibition as an anticoagulant, we designed and synthesized 3-(amidinoaryl)-2-[4-[(3S)-3-pyrrolidinyloxy]phenyl]propanoi c acid derivatives as low molecular weight, nonpeptidic, orally active FXa inhibitors. These derivatives exhibited potent and highly selective anti-FXa activity in vitro and anticoagulant activity on oral administration. The most promising compound, (2S)-2-[4-[[(3S)-1-acetimidoyl-3-pyrrolidinyl]oxy]phenyl]- 3-(7-amidino-2-naphthyl)propanoic acid hydrochloride pentahydrate (4,DX-9065a), inhibited 50% of FXa activity (IC50) at 0.07 microM, doubled plasma recalcification time (PRCT) at 0.5 microM, and significantly prolonged activated partial thromboplastin time (APTT) at a dose of 100 mg/kg on oral administration. In contrast with FXa inhibition, 4 showed no activity against thrombin (IC50 > 2000 microM).
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PMID:Dibasic (amidinoaryl)propanoic acid derivatives as novel blood coagulation factor Xa inhibitors. 816 62

By developing 6-amidino-2-naphthyl 4-guanidinobenzoate (I, FUT-175) as a basic structure, its various derivatives were synthesized and their inhibitory activities on trypsin, plasmin, kallikrein, thrombin, C1r and C1s as well as on complement-mediated hemolysis were examined. The protective effect of these compounds on complement-mediated Forssman shock was also examined in guinea pigs. 6-Amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]-benzoate (41, FUT-187) was found to be a suitable compound for oral administration with anti-complement activity superior to that of compound I.
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PMID:Synthesis and structure-activity study of protease inhibitors. V. Chemical modification of 6-amidino-2-naphthyl 4-guanidinobenzoate. 844 13


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