Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Catechol analogs inhibit the formation of hydroxylysine-derived intermolecular collagen cross links in tissue cultures of chick embryo calvaria. Formation of intermolecular collagen cross links was measured following incorporation of [14C]lysine, reduction with sodium borohydride, and elution from an ion exchange column with a pyridine-formate gradient. Cultures grown in the presence of 10(-3) M catechol, 10(-3) M dopamine, 10(-3) M L-dopa, or 10(-3) M D,L-serine-(2,3,4-trihydroxybenzyl)-hydrazide demonstrated between 43 and 84% inhibition of hydroxylysine formation. Collagen biosynthesis was not diminished in these cultures as compared to controls without additions or with beta-aminopropionitrile when measured by collagenase digestion. The formation of hydroxylysine-derived intermolecular cross links was inhibited 34 to 93% for 5,5'-dihydroxylysinonorleucine and 7 to 71% for 5-hydroxylysinonorleucine. The catechol analogs also inhibit the activity of lysyl hydroxylase as measured by specific tritium release as triated water from an L-[4,5-3H]lysine-labeled unhydroxylated collagen substrate prepared from chick calvaria. Since catechol analogs inhibit the formation of hydroxylysine in a cell-free assay, these compounds must pass into the cells of calvaria in this culture system to inhibit intracellular hydroxylysine formation and subsequently to diminish the reducible intermolecular cross links of the newly synthesized collagen.
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PMID:In vitro inhibition of collagen cross links by catechol analogs. 1 15

The effects of smokeless tobacco extract (STE) and prolyl hydroxylase inhibitors on protein synthesis by isolated osteoblast-like cells were compared. STE and 2,2'dipyridyl markedly inhibited alkaline phosphatase (Alpase) and [3H]proline hydroxylation without affecting glycolysis (lactate production). However, pyridine 2,5-dicarboxylate (2,5-PDC) did not inhibit [3H] proline hydroxylation, Alpase activity, or glycolysis at moderate concentrations. The [3H]hydroxyproline to [3H]proline ratio in the cell layers demonstrated a concentration-dependent decrease with increasing STE and inhibitor concentrations. In the cell layers, the collagenous protein (CP) content was decreased after exposure to STE, 2,2'dipyridyl, and 2,5-PDC and the noncollagenous protein (NCP) content was decreased after exposure to STE and 2,5-PDC. However, the effects on CP were at least twofold greater than on NCP. Similar results were observed regarding protein released to the culture medium. These data demonstrate that STE, like 2,2'dipyridyl, inhibits the hydroxylation of proline and the synthesis of collagenase-digestible protein.
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PMID:Comparison of the effects of smokeless tobacco extract with the effects of prolyl hydroxylase inhibitors on collagenous and noncollagenous protein synthesis by osteoblasts. 166 21

SR 26831 ([[5-(2-chloro-benzyl-2-(terbutyloxycarbonyl)]-4,5,6,7- tetrahydrothieno(3,2-c)pyridine]N-oxide) is the first member of a new class of human leukocyte elastase inhibitors. SR 26831 inhibited in a dose-dependent manner elastases from human leukocytes or pancreas with IC50 values of 80 +/- 2.6 nM and 4.8 +/- 0.12 microM, respectively. Steady-state studies revealed that SR 26831 behaved like a noncompetitive, irreversible inhibitor of both types of enzymes. SR 26831 inhibited in a dose-dependent manner degradation of [3H]elastin and [3H]collagens (types I and IV) by human leukocyte elastase (IC50 values were between 1.2 and 1.8 microM). In this respect, SR 26831 was 3- to 20-fold more active than alpha-1-antitrypsin. SR 26831 was also highly selective for elastases inasmuch as it did not inhibit pepsin, collagenase, trypsin, alpha-chymotrypsin, factor Xa, plasmin, kallikrein, cathepsins B, C, D and G and thrombin. In the rabbit, SR 26831 was cleared rapidly from blood after i.v. injection, but affected intracellular leukocyte elastase activity shortly after either i.v. or p.o. administration. In the rat, i.v. or p.o. administration of SR 26831 prevented in a dose-dependent manner acute lung injury induced by intratracheal instillation of human leukocyte elastase. SR 26831 (1 mg/kg) was still efficient when it was administered 90 min before elastase instillation and was also able to limit further hemorrhage development in response to elastase, after it had begun. SR 26831 may therefore be of therapeutic value in the treatment of diseases such as rheumatoid arthritis or pulmonary emphysema thought to be due to the destructive action of leukocyte elastase.
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PMID:Biochemical and pharmacological activities of SR 26831, a potent and selective elastase inhibitor. 173 26

Taste discs were dissected from the tongue of R. ridibunda and their cells dissociated by a collagenase/low Ca/mechanical agitation protocol. The resulting cell suspension contained globular epithelial cells and, in smaller number, taste receptor cells. These were identified by staining properties and by their preserved apical process, the tip of which often remained attached to an epithelial (associated) cell. When the patch pipette contained 110 mM KCl and the cells were superfused with NaCl Ringer's during whole-cell recording, the mean zero-current potential of 22 taste receptor cells was -65.2 mV and the slope resistance 150 to 750 M omega. Pulse-depolarization from a holding voltage of -80 mV activated a transient TTX-blockable inward Na current. Activation became noticeable at -25 mV and was half-maximal at -8 mV. Steady-state inactivation was half-maximal at -67 mV and complete at -50 mV. Peak Na current averaged -0.5 nA/cell. The Ca-ionophore A23187 shifted the activation and inactivation curve to more negative voltages. Similar shifts occurred when the pipette Ca was raised. External Ni (5 mM) shifted the activation curve towards positive voltages by 10 mV. Pulse depolarization also activated outward K currents. Activation was slower than that of Na current and inactivation slower still. External TEA (7.5 mM) and 4-amino-pyridine (1 mM) did not block, but 5 mM Ba blocked the K currents. K-tail currents were seen on termination of depolarizing voltage pulses. A23187 shifted the IK(V)-curve to more negative voltages. Action potentials were recorded when passing pulses of depolarizing outward current. Of the frog gustatory stimulants, 10 mM Ca caused a reversible 5- to 10-mV depolarization in the current-clamp mode. Quinine (0.1 mM, bitter) produced a reversible depolarization accompanied by a full block of Na current and, with slower time-course, a partial block of K currents. Cyclic AMP (5 mM in the external solution or 0.5 microM in the pipette) caused reversible depolarization (to -40 to -20 mV) due to partial blockage of K currents, but only if ATP was added to the pipette solution. Similar responses were elicited by stimulating the adenylate cyclase with forskolin. Blockage of cAMP-phosphodiesterase enhanced the response to cAMP. These results suggest that cAMP may be one of the cytosolic messengers in taste receptor cells. Replacement of ATP by AMP-PNP in the pipette abolished the depolarizing response to cAMP.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Patch-clamp study of isolated taste receptor cells of the frog. 244 95

This investigation was initiated to characterize the stimulation of insulin secretion by phenazine methosulfate (PMS). Islets of Langerhans, isolated by the collagenase method from normal rats and rats pre-injected with either streptozotocin or 6-aminonicotinamide, were exposed to PMS under various experimental conditions and insulin secretion in response to PMS, glucose and pyridine nucleotides was determined. Insulin releasing action of PMS was dose-, time- and temperature-related, occurred in the absence of glucose, and was inhibited by epinephrine, but not by mannoheptulose. In the perifusion system, the pattern of response induced by PMS was spike-like release reaching a maximum in 5 min and declining rapidly to half-maximal value in 10 min. After exposure of islets to beta-cytotoxin either in vivo or in vitro, complete reversal of the cytotoxic effect was obtained with PMS which induced release of insulin in both normal and beta-cytotoxin islets pre-treated. It is concluded that islets depleted of coenzymes could still secrete insulin in response to a reactive proton donor, which might act by substituting for coenzymes and that the immediate action of beta-cytotoxins does not completely arrest the secretory mechanisms in islets of Langerhans.
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PMID:The characterization of phenazine methosulfate stimulated insulin secretion. 295 17

Orthotopic liver transplantation is the most effective treatment for fulminant hepatic failure. As an alternative treatment, an efficient extracorporeal bioartificial liver should contain a large yield of functional hepatocytes with an immunoprotective barrier, for providing temporary adequate metabolic support to allow spontaneous liver regeneration or for acting as a bridge toward transplantation. Survival, proliferation, and functions of porcine hepatocytes were evaluated in primary cultures and after embedding in alginate beads, which were subsequently coated with a membrane made by a transacylation reaction between propylene glycol alginate and human serum albumin. Disruption of total pig livers by collagenase perfusion/recirculation allowed the obtention of up to 10(11) hepatocytes with a viability greater than 95%. Hepatocytes in conventional cultures or embedded in coated alginate beads survived for about 10 days, secreted proteins, particularly albumin, and maintained several phase I and II enzymatic activities, namely ethoxyresorufin-O-deethylase, oxidation of nifedipine to pyridine, phenacetin deethylation to paracetamol, glucuroconjugation of paracetamol, and N-acetylation of procainamide. Typical features of mitosis and [3H]thymidine incorporation indicated that porcine hepatocytes proliferated in both conventional cultures and alginate beads. The efficacy of the membrane surrounding alginate beads for protecting cells from immunoglobulins was tested by embedding HLA-typed human lymphocytes, which were subsequently incubated with specific anti-HLA immunoglobulin G and complement. These data show that large yields of porcine hepatocytes that are embedded in coated alginate beads remain functional and are isolated from large molecular weight molecules, such as immunoglobulins. This system represents a promising tool for the design of an extracorporeal bioartificial liver, containing xenogeneic hepatocytes, to treat acute liver disease in humans.
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PMID:Survival, proliferation, and functions of porcine hepatocytes encapsulated in coated alginate beads: a step toward a reliable bioartificial liver. 908 17

The solution structure of the catalytic fragment of human fibroblast collagenase (MMP-1) complexed with a sulfonamide derivative of a hydroxamic acid compound (CGS-27023A) has been determined using two-dimensional and three-dimensional heteronuclear NMR spectroscopy. The solution structure of the complex was calculated by means of hybrid distance geometry-simulated annealing using a combination of experimental NMR restraints obtained from the previous refinement of the inhibitor-free MMP-1 (1) and recent restraints for the MMP-1:CGS-27023A complex. The hydroxamic acid moiety of CGS-27023A was found to chelate to the "right" of the catalytic zinc where the p-methoxyphenyl sits in the S1' active-site pocket, the isopropyl group is in contact with H83 and N80, and the pyridine ring is solvent exposed. The sulfonyl oxygens are in hydrogen-bonding distance to the backbone NHs of L81 and A82. This is similar to the conformation determined by NMR of the inhibitor bound to stromelysin (2, 3). A total of 48 distance restraints were observed between MMP-1 and CGS-27023A from 3D 13C-edited/12C-filtered NOESY and 3D 15N-edited NOESY experiments. An additional 18 intramolecular restraints were observed for CGS-27023A from a 2D 12C-filtered NOESY experiment. A minimal set of NMR experiments in combination with the free MMP-1 assignments were used to assign the MMP-1 (1)H, 13C, and 15N resonances in the MMP-1:CGS-27023A complex. The assignments of CGS-27023A in the complex were obtained from 2D 12C-filtered NOESY and 2D 12C-filtered TOCSY experiments.
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PMID:NMR solution structure of the catalytic fragment of human fibroblast collagenase complexed with a sulfonamide derivative of a hydroxamic acid compound. 1035 19

In an effort to identify promising non-hydroxamate inhibitors of matrix metalloproteinases (MMPs) several new zinc-binding groups (ZBGs) based on pyridine-derived or aza-macrocycle chelators have been examined. Fluorescence-based enzyme assays have been used to determine the IC50 values for these ZBGs against MMP-1, MMP-3, and anthrax lethal factor (LF). Many of these ligands were found to be remarkably potent, with IC50 values as much as 185-fold lower than that found for acetohydroxamic acid. These ligands are proposed to be more selective "warheads" for the inhibition of metalloenzymes that contain Zn2+ versus other metal ions at their active site.
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PMID:A new role for old ligands: discerning chelators for zinc metalloproteinases. 1652 91

Inflammatory and infectious conditions were simulated in cultures of ras/myc-transformed serum-free mouse embryo (ras/myc SFME) cells, using interferon-gamma (IFN-gamma, 100 units/ml) and lipopolysaccharide (LPS, 0.5 microg/ml) co-treatment for 24 h, to investigate their effects on the expression of inducible nitric oxide synthase (iNOS) mRNA and the production of NO. Aminoguanidine (AG, 1 mM; an NOS inhibitor) along with IFN-gamma and LPS, S-nitroso-N-acetyl-DL-penicillamine (SNAP, 100 microM; an NO donor) and/or (+/-)-N-[(E)-4-Ethyl-2-[(Z)-hydroxyimino]-5-nitro-3-hexene-1-yl]-3-pyridine carboxamide (NOR4, 100 microM; an NO donor), were also added to analyze the possible association of NO with matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1). Co-treatment of cells with IFN-gamma and LPS increased iNOS mRNA expression, NO production, MMP-9 mRNA expression, and 105 kDa MMP-9 production. Additional treatment with the NOS inhibitor AG inhibited NO production, but did not down-regulate the expression of MMP-9 mRNA or 105 kDa MMP-9. The NO donors SNAP and NOR4 did not affect the expression of MMP-9 mRNA, 105 kDa MMP-9 or TIMP-1 mRNA. These results suggest that ras/myc SFME cells respond to infectious and inflammatory conditions and can enhance malignancy as cancer cells due to their increased levels of NO and MMP-9 production, but that NO is not directly associated with MMP-9 in these cells.
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PMID:Ras/myc-transformed serum-free mouse embryo cells under simulated inflammatory and infectious conditions increase levels of nitric oxide and matrix metalloproteinase-9 without a direct association between them. 1766 Sep 54