Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glu-198 of human matrilysin is a conserved residue in the matrix metalloproteinases and is considered to play an important role in catalysis by acting as a general base catalyst toward the zinc-bound water molecule, on the basis of mechanistic proposals for other zinc proteases. In the present study, Glu-198 is mutated into Asp, Cys, Gln, and Ala, and the zinc binding properties, kinetic parameters, and pH dependence of each mutant are determined in order to examine the role of Glu-198 in catalysis. The mutations chosen either modify (C and D) or eliminate (A and Q) the general base properties of residue-198. All the mutants bind 2 mol of zinc per mol of enzyme, indicating that Glu-198 is not crucial to the binding of the catalytic zinc to the enzyme. The value of kcat/Km for the E198D mutant is only 4-fold lower than that of wild-type enzyme at the pH optimum of 7.5, while that for the E198C mutant is decreased by 160-fold. The E198Q and E198A enzymes containing the mutations that have eliminated the nucleophilic and acid/base properties of the residue are still active, having lower kcat/Km values of 590- and 1900-fold, respectively. The decrease in activity of all the mutants is essentially due to a decrease in kcat. The kcat/Km values of the mutants as a function of pH display broad bell-shaped curves that are similar to the wild-type enzyme. The acidic pKa value is not greatly affected by the change in the chemical properties of residue-198. The similarity in the pH profiles for the mutant and wild-type enzymes indicates that the ionization of Glu-198 is not responsible for the acidic pKa. Ionization of the zinc-bound water may be responsible for this pKa since the three His ligands and the scaffolding of the matrilysin catalytic zinc site are different from that observed in carboxypeptidase A and would predict a lower pKa for the metal-bound water. If the zinc-bound water is the nucleophile in the reaction, the role of Glu-198 in catalysis may be to stabilize the transition state or act as a general acid catalyst after the rate-determining step.
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PMID:Site-directed mutagenesis of the active site glutamate in human matrilysin: investigation of its role in catalysis. 939 37

States of tryptophyl residues and stability of human matrilysin were studied. The activation energy for the thermal inactivation of matrilysin was determined to be 237 kJ/mol, and 50% of the activity was lost upon incubation at 69 degrees C for 10 min. The activity was increased by adding NaCl, and was doubled with 3 M NaCl. Denaturation of matrilysin by guanidine hydrochloride (GdnHCl) and urea was monitored by fluorescence change of tryptophyl residues. Half of the change was observed at 2.2-2.7 M GdnHCl, whereas no change was observed even with 8 M urea. Half of the inactivation was induced at 0.8 M GndHCl and at 2 M urea. The presence of an inactive intermediate with the same fluorescence spectrum as the native enzyme was suggested in the denaturation. Matrilysin contains four tryptophyls, and their states were examined by fluorescence-quenching with iodide and cesium ions and acrylamide. No tryptophyls in the native enzyme were accessible to I(-) and Cs(+), and 2.4 residues were accessible to acrylamide. Based on the crystallographic study, Trp154 is water-accessible, but it should be in a crevice not to contact with I(-) and Cs(+). All tryptophyls in the GdnHCl-denatured enzyme were exposed to the quenchers, while a considerable part was inaccessible in the urea-denatured one.
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PMID:States of tryptophyl residues and stability of recombinant human matrix metalloproteinase 7 (matrilysin) as examined by fluorescence. 1096 33

To clarify the possible link between radicals and cytotoxicity of eugenol-related compounds, dimeric compounds were synthesized from eugenol (4-allyl-2-methoxy-phenol), butylated hydroxyanisole (BHA) (2-t-butyl-4-methoxyphenol) or MMP (2 methoxy-4-methylphenol); bis-EUG (3,3'-dimethoxy-5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol), bis-BHA (3,3'-di-t-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diol), and bis-MMP (3,3'-di-methoxy-5,5'-dimethyl-1,1'-biphenyl-2,2'-diol). The cytotoxic activity of these compounds was determined using a salivary gland tumor cell line (HSG), oral squamous cell carcinoma cell line (HSC-2) and human promyelocytic leukemia cell line (HL-60). A parabolic relationship between the cytotoxicity and log P (the octanol-water partition coefficient) was observed, showing that both BHA and bis-MMP, with a log P of 3-4, were the most cytotoxic. The cytotoxic activity of the 2-methoxy derivatives, eugenol, MMP and bis-MMP, against HSG cells was significantly enhanced by visible-light irradiation, possibly due to their high redox potential. Electron spin resonance (ESR) spectroscopy indicated that eugenol and BHA alone produced radicals under alkaline conditions (pH > 9.5), and eugenol most efficiently scavenges reactive oxygen species (O2-). Antioxidative reactivity of eugenol-related compounds was determined by measuring the inhibiting periods of the AIBN (2,2'-azobisisobutyronitrile)/MMA (methyl methacrylate) polymerization system, and the number of moles of peroxy radical trapped by moles of the relevant phenols (stoichiometric factor, n). It was found that the n values of eugenol and MMP were approximately 1, whereas those of BHA >2, suggesting that eugenol and MMP undergo dimerization through radical-radical couplings through quinone methides, whereas BHA undergoes the competitive interaction with poly-MMA radicals after oxidation by AIBN-peroxy radicals. BHA was an efficient peroxy radical-scavenger, but possibly reacted with polymer radicals of the lipid, thus mediating the cytotoxicity. The n value of bis-BHA was two, whereas those of bis-EUG and bis-MMP were 1.6-1.7, suggesting that the latter were further oxidized. The enthalpies of phenoxyl radical formation were determined using the semi-empirical PM3 quantum-mechanical method and the possible link to redox potential was discussed.
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PMID:Radical generation, radical-scavenging activity, and cytotoxicity of eugenol-related compounds. 1131 78

Implantation in humans is a complex process that is temporally and spatially restricted. Over the past decade, using a one-by-one approach, several genes and gene products that may participate in this process have been identified in secretory phase endometrium. Herein, we have investigated global gene expression during the window of implantation (peak E2 and progesterone levels) in well characterized human endometrial biopsies timed to the LH surge, compared with the late proliferative phase (peak E2 level) of the menstrual cycle. Tissues were processed for poly(A(+)) RNA and hybridization of chemically fragmented, biotinylated cRNAs on high density oligonucleotide microarrays, screening for 12,686 genes and expressed sequence tags. After data normalization, mean values were obtained for gene readouts and fold ratios were derived comparing genes up- and down-regulated in the window of implantation vs. the late proliferative phase. Nonparametric testing revealed 156 significantly (P < 0.05) up-regulated genes and 377 significantly down-regulated genes in the implantation window. Up-regulated genes included those for cholesterol trafficking and transport [apolipoprotein (Apo)E being the most induced gene, 100-fold], prostaglandin (PG) biosynthesis (PLA2) and action (PGE2 receptor), proteoglycan synthesis (glucuronyltransferase), secretory proteins [glycodelin, mammaglobin, Dickkopf-1 (Dkk-1, a Wnt inhibitor)], IGF binding protein (IGFBP), and TGF-beta superfamilies, signal transduction, extracellular matrix components (osteopontin, laminin), neurotransmitter synthesis (monoamine oxidase) and receptors (gamma aminobutyric acid A receptor pi subunit), numerous immune modulators, detoxification genes (metallothioneins), and genes involved in water and ion transport [e.g. Clostridia Perfringens Enterotoxin (CPE) 1 receptor (CPE1-R) and K(+) ion channel], among others. Down-regulated genes included intestinal trefoil factor (ITF) [the most repressed gene (50-fold)], matrilysin, members of the G protein-coupled receptor signaling pathway, frizzled-related protein (FrpHE, a Wnt antagonist), transcription factors, TGF-beta signaling pathway members, immune modulators (major histocompatibility complex class II subunits), and other cellular functions. Validation of select genes was conducted by Northern analysis and RT-PCR using RNA from endometrial biopsies obtained in the proliferative phase and the implantation window and by RT-PCR using RNA from cultured endometrial epithelial and stromal cells. These approaches confirmed up-regulation of genes corresponding to IGFBP-1, glycodelin, CPE1-R, Dkk-1, mammaglobin, and ApoD and down-regulation for PR membrane component 1, FrpHE, matrilysin, and ITF, as with the microarray data. Cultured endometrial epithelial cells were found to express mRNAs for glycodelin, CPE-1R, Dkk-1, the gamma aminobutyric acid A receptor pi subunit, mammaglobin, matrilysin, ITF and PR membrane component 1. The expression of IGFBP-1, CPE1-R, Dkk-1, and ApoD mRNAs increased upon decidualization of stromal cells in vitro with progesterone after E2 priming, whereas FrpHE decreased, consistent with the microarray results. Overall, the data demonstrate numerous genes and gene families not heretofore recognized in human endometrium or associated with the implantation process. Reassuringly, several gene products, known to be differentially expressed in the implantation window or in secretory endometrium, were verified, and the striking regulation of select secretory proteins, water and ion channels, signaling molecules, and immune modulators underscores the important roles of these systems in endometrial development and endometrial-embryonic interactions. In addition, the current study validates using high density oligonucleotide microarray technology to investigate global changes in gene expression in human endometrium.
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PMID:Global gene profiling in human endometrium during the window of implantation. 1202 Nov 76

To clarify the possible link between radicals and the cytotoxicity of eugenol-related compounds, 2-allyl-4-X-phenols (2-allyl-4-chlorophenol (1), 2-allyl-4-phenylphenol (2), 2-allyl-4-methoxyphenol (3), 2-allyl-4-acetylphenol (4), 2-allyl-4-nitrophenol (5), 2-allyl-4-t-butylphenol (6), 2-allyl-4-methyphenol (7), 2-allyl-4-bromophenol (8), 2,4-dimethoxyphenol (9)), and dimeric compounds from eugenol (4-allyl-2-methoxyphenol), BHA (2-t-butyl-4-methoxyphenol) or MMP (2-methoxy-4-methylphenol); bis-EUG (3,3'-dimethoxy-5,5'-di-2-propenyl-1, 1'-biphenyl-2,2'-diol) (10), bis-MMP (3,3'-dimethoxy-5,5'-dimethyl-1,1'-biphenyl-2,2'-diol) (11) bis-BHA (3,3'-di-t-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diol) (12) were synthesized. The radical production, radical-scavenging activity and the cytotoxicity of these synthetic compounds and conventional antioxidants (i.e. butylhydroxytoluine, BHT; butylhydroxyanisole, BHA; alpha-tocopherol (alpha-Toc); eugenol, phenol) were studied. Erectron spin resonance (ESR) spectroscopy suggested that compounds of 3, 6, 9, eugenol and BHA, but not compounds of 10, 11, and 12 produced radicals in alkaline solutions (pH>9.5) and compounds, 3, eugenol and 9 most efficiently scavenged reactive oxygen species (ROS, O(2)(-)). The cytotoxic activity of 6 toward human submandibular gland carcinoma (HSG) cells was the highest and was 1000-fold greater than that of eugenol and 100-fold greater than that of BHA, possibly due to the high hydrophobicity and stable phenoxy radicals of this compound. The kinetic polymerization method in the presence of methyl methacrylate (MMA), an antioxidant, and 2,2'-azobisisobutyronitrile (AIBN) was developed for the measurements of the number of moles of peroxy radicals trapped by moles of the relative phenols (stoichiometric factors, n), the inhibition rate of polymerization (R(inh)), and the inhibition rate constants (k(inh), the rate constants for scavenging of radicals by an antioxidant). The n values of conventional phenolic antioxidants decreased in the order: alpha-Toc>BHT>eugenol>phenol. Those for eugenol and phenol, less hindered phenols, were much less than two, whereas those for alpha-Toc and BHT, hindered phenols, were approximately two. The R(inh) of alpha-Toc significantly increased tcompared with that of BHT, eugenol and phenol. The k(inh) of the polymer radicals of the MMA reaction with conventional phenolic antioxidants was a low value of 1-2x10(2) M(-1) s(-1), suggesting that the antioxidants trapped radicals quickly. The comparative cytotoxicity of methoxyphenols against HSG cells was investigated. The cytotoxic activity of dimers of 10 and 12 was markedly lower than that of their corresponding monomers, whereas that of the dimer of MMP, 11 was not reduced even after the dimerization. In particular, visible-light (VL) exposure enhanced the cytotoxicity of 11 similar to the monomers of eugenol, BHA and MMP. Changes in BDE (ph(O-H)) (homolytic bond dissociation energy) for phenols is well known to be associated with the n and k(inh) values, and consequently the cytotoxic activity. Thus, the BDE was calculated using a PM3 semiempirical method. The n and k(inh) values for monophenols, but not for dimers were correlated to the BDE, possibly due to the steric hindrance of orthosubstituents of dimers. The quantitative structure-activity relationship (QSAR) of eugenol-related compounds was investigated, indicating that logP (octanol-water partition coefficients), the redox potential measured in culture medium, was effective as a term for QSAR. A parabolic relation between the cytotoxic activity and the logP or the redox potential, but not the BDE was observed with an optimum value. In conclusion, the cytotocity of eugenol-related compounds was significantly associated with the activity of the production of phenoxyl radicals, their stability of the subsequent quinonemethide (QM) and the hydrophobicity.
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PMID:Antioxidant and prooxidant action of eugenol-related compounds and their cytotoxicity. 1212 94

We have recently observed marked increases in MMP-derived aggrecan fragments in extracts of cartilage stimulated with IL-1. The fragments were detected with an anti-DIPEN neoepitope antibody that is specific for fragments generated by MMP cleavage at the DIPEN(341) F(342)FGVG site. Because our results contrasted with another study, we systematically compared our methods with other published methods. We now report that DIPEN(341) neoepitope can be generated post-culture, by dialysing GuHCl(1)-denatured samples against unbuffered, deionized water at 4 degrees C. We show that EDTA must be included in the GuHCl extractant, as well as the dialysis buffer, in order to block post-culture processing of aggrecan by MMPs.
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PMID:Matrix metalloproteinases are active following guanidine hydrochloride extraction of cartilage: generation of DIPEN neoepitope during dialysis. 1222 7

Lung injury and inflammation are associated with exposure to various types of particulate air pollutants. The present study was used to determine whether metalloproteinases (MMPs) are secreted after instilling dust samples into the lung, and to relate levels of specific MMPs to different fractions of the ambient air particle sample EHC-93. Rats received an intratracheal injection of 5 mg dust samples in 0.5 ml water and were killed at intervals from 4 hours to 28 days later particle samples were EHC-93 whole dust, and the insoluble, leached, and soluble fractions of the same dust. Samples prepared from EHC-2K dust were also used, as were solutions of zinc and copper chloride. All samples induced inflammation as measured by increased inflammatory cells in bronchoalveolar lavage (BAL) fluid; the highest levels were found 1 to 3 days after instilling the whole dust. This dust also induced production of MMP-2 and MMP-9 as shown in zymograms. The leached dust induced predominantly MMP-9, which was maximal at 4 hours and 1 day. In contrast, the soluble fraction induced almost exclusive 4 MMP-2, also maximal at 4 hours and 1 day; this enzyme was also produced in response to soluble zinc, the most prevalent soluble metal in the EHC samples. The results demonstrate the rapid production and secretion of MMPs in the lung after particle deposition. A differential pattern of MMP production is seen with MMP-9, likely from inflammatory cells, being produced in response to the insoluble particles, and MMP-2, likey from epithelial cells, being produced in response to the water-soluble fraction of the atmospheric dust.
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PMID:Differential production of metalloproteinases after instilling various urban air particle samples to rat lung. 1288 50

A procedure is described for the rapid determination of the intra-erythrocyte concentration of 6-mercaptopurine (6-MP) and its metabolites, 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP). Erythrocytes (8 x 10(8) cells) in 350 microl Hanks solution containing 7.5 mg dithiothreitol were treated with 50 microl 70% perchloric acid. The precipitate was removed by centrifugation (13,000 g) and the supernatant hydrolyzed at 100 degrees C for 45 min. After cooling, 100 microl was analyzed directly by HPLC using a Radialpack Resolve C18 column eluted with methanol-water (7.5:92.5, v/v) containing 100 mM triethylamine. 6-TG, 6-MP and the hydrolysis product of 6-MMP, 4-amino-5-(methylthio)carbonyl imidazole, were monitored at 342, 322 and 303 nm using a Shimadzu SPD-M10A diode array UV detector. The analytes eluted at 5.3, 6.0 and 10.2 min, respectively. The calibration curves were linear (r(2) > 0.998), and the analytical recoveries were 73.2% for 6-TG, 119.1% for 6-MP and 97.4% for 6-MMP. The intra- and inter-assay variations were highest for 6-MP (9.6 and 14.3%, respectively). The lowest detectable concentrations were 3, 3 and 25 pmol/8 x 10(8) erythrocytes for 6-TG, 6-MP and 6-MMP, respectively. The quantification limits (coefficients of variation <15%) were 8, 10 and 70 pmol/8 x 10(8) erythrocytes for 6-TG, 6-MP and 6-MMP, respectively. The method was applied to the analysis of 183 samples from 36 children under chemotherapy for acute lymphoblastic leukemia. The concentrations of the metabolites in the red cells of the patients ranged from 0 to 1934 pmol/8 x 10(8) erythrocytes for 6-TGN, and from 0 to 105.8 and 0 to 45.9 nmol/8 x 10(8) erythrocytes for 6-MP and 6-MMP, respectively. The procedure gave results that were in agreement with those obtained with other methods designed to detect cases of non-compliance with treatment, including patient interviews and medical evaluation, among others, demonstrating its applicability to monitoring the treatment of leukemic children.
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PMID:An improved HPLC method for the quantitation of 6-mercaptopurine and its metabolites in red blood cells. 1510 25

Matrix metalloproteinases (MMPs) and the related tumor necrosis factor converting enzyme (TACE) are involved in tissue remodeling, cell migration, and processing of signaling molecules, such as cytokines and adhesion molecules. Fluorescence-quenched peptide substrates have been widely used to quantitate the actual enzymatic activity of MMPs. However, the various MMPs have very different specific activities toward these substrates. This restricts their value for the determination of composite proteolytic activity of mixtures of metalloproteinases in biological fluids. The N-terminal elongation of the most widely used MMP substrate (FS-1) with a Lys to the sequence Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH(2) (FS-6) yields a fluorogenic peptide with improved substrate properties. As compared to FS-1, the specificity constant (kcat/Km) of FS-6 for collagenases (MMP-1, MMP-8, MMP-13) and MT1-MMP (MMP-14) is increased two- to ninefold and threefold, respectively, while those for gelatinases and matrilysin remain equally high. Using high-performance liquid chromatography-fluorescence detection, MMP activity can be quantitated in the picomolar range. FS-6 shows up to twofold higher specificity constants (kcat/Km of 0.8x10(6)M(-1)s(-1)) for TACE, as compared to standard substrates Mca-PLAQAV-Dpa-RSSSAR-NH(2) and Dabcyl-LAQAVRSSSAR-EDANS. FS-6 is fully water soluble and thus allows measurement of metalloproteinase activity in tissue culture conditions, e.g., on the surface of viable cells in situ.
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PMID:Characterization of Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2, a fluorogenic substrate with increased specificity constants for collagenases and tumor necrosis factor converting enzyme. 1511 93

Examples of the commercial trap Mosquito Magnet Pro (MMP emitting attractant 1-octen-3-ol in carbon dioxide 500 mL/min generated from propane fuel), were run 24 h/day on the Isle of Skye, Scotland, during June-August 2001 and evaluated for catching Culicoides biting midges (Diptera: Ceratopogonidae). From 30 days trapping, the catch averaged 2626 +/- 1358 Culicoides females/trap/day (mean +/- SE, range 558 +/- 139 to 6088 +/- 3597, for five sets of six consecutive nights), predominantly the pest Culicoides impunctatus Goetghebuer (68% overall), plus C. vexans (Staeger) > C. delta Edwards > C. pulicaris (L.) > C. lupicaris Downs & Kettle > C. albicans (Winnertz) > other Culicoides spp. Attempts were made to enhance the odour baiting system by adding hexane-extracts (2.1 mg/day) of hair samples from large host animals, resulting in the following effects on Culicoides collections: sheep - 53 %, red deer - 26 %, calf + 20%, pony + 40%, water buffalo + 262%, with greatest increases for C. impunctatus and C. pulicaris. Serial concentrations of these animal extracts (10(-1) - 10(-3) x 2.2 g/mL) were assayed on parous female C. impunctatus response in a Y-tube olfactometer (air-flow 150 mL/min), and by electroantennogram (EAG) on Culicoides nubeculosus Meigen laboratory-reared parous females. Positive behavioural responses to host odours were dose-dependent: the water buffalo extract being most active (threshold 0.22 g/mL), similar to deer, whereas other host extracts were > or = 10-fold less active. Correspondingly, the EAG threshold was lowest for water buffalo, 10-fold greater for deer, calf and pony, but not detected for sheep. If the active component(s) of these host extracts can be identified and synthesized, they might be employed to improve the capture of Culicoides midges for local control by removal trapping.
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PMID:Culicoides midge trap enhancement with animal odour baits in Scotland. 1564 99


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