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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Collagenases (EC 3.4.24.3) from human skin, rat skin and rat uterus were inhibited by the chelating agents EDTA, 1,10-phenanthroline and tetraethylene pentamine in the presence of excess Ca2+, suggesting that a second metal ion participates in the activity of the enzyme. Collagenase inhibition by 1,10-phenanthroline could be both prevented and reversed by a number of transition metal ions, specifically Zn2+, Co2+, Fe2+ and Cu2+. However, Zn2+ is effective in five-fold lower molar concentrations (1-10(-4) M) than the other ions. Furthermore, Zn2+ was the only ion tested able to prevent and reverse the inhibition of collagenase by EDTA in the presence of excess Ca2+. Atomic absorption analysis of purified collagenase for Zn2+ showed that Zn2+ was present in the enzyme preparations, and that the metal co-purifies with collagenase during column chromatography.
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PMID:Evidence for mammalian collagenases as zinc ion metalloenzymes. 19 65

1. Carotid body chemoreceptors were removed intact from adult rats and subjected to protease and collagenase enzymatic digestion of connective tissue. 2. Recordings from the sinus nerve demonstrated that chemotransduction remains intact for at least 2-3 h after isolation, enzyme exposure, and suspension in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-buffered saline at room PO2. 3. After mechanical dissociation, the interrelationship between changes in extracellular PO2 and pH and relative changes in intracellular calcium (Ca2+i) were observed in glomus cells with the use of fluo-3 and confocal microscopy. 4. Brief (60-s) decreases in PO2 from 150 mmHg to near 0 mmHg, at nadir, caused a marked reduction in Ca2+i (peak delta F/F0 = -32 +/- 3%, mean +/- SE, n = 43), which rapidly recovered after reoxygenation. The decrease was reproducible from trial to trial and was also observed in HCO3(-)-buffered Ringer solution. 5. Superfusion with Ca(2+)-free HEPES saline with 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) blocked the hypoxia-induced increase in afferent chemoreceptor activity in vitro. Superfusion of the same solution over isolated cells for 15 min caused a large decrease in Ca2+i (-34 +/- 7%, n = 16). 6. In the presence of Ca(2+)-free HEPES, reoxygenation caused calcium fluorescence to increase. This suggests that the Ca2+ decrease during hypoxia is due, at least partially, to binding to an intracellular site. 7. Extracellular cobalt (1 mM, 15 min) also reversibly blocked the chemoreceptor response to hypoxia, in vitro, and caused a reduction in Ca2+i (delta F/F0 = -37 +/- 8%, n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hypoxia decreases intracellular calcium in adult rat carotid body glomus cells. 162 63

Large amounts of metal and polyethylene debris and high ion readings are found in capsule and fibrous membranes of both loose titanium and cobalt-chromium stems. Prostaglandin E2, interleukin-1, and collagenase levels are elevated when compared to control values with collagenase having the highest and most consistent elevations. Synovial fluid and blood ion readings were elevated in loose cemented and cementless stems made from both materials. Blood ion readings were not elevated in fixed stems. Fixed stems had much less particulate debris in soft tissues. The data showed that failure of most metal hip stems was initially due to a mechanical cause, with high debris and ion counts occurring secondarily in capsule and fibrous membranes. Particulate debris and high ion readings are primarily a focal problem contained by the periprosthetic fibrous connective-tissue encapsulation within the femoral canal and joint capsules. No systemic problems were manifest in any of the patients examined and followed in this study.
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PMID:Histologic, biochemical, and ion analysis of tissue and fluids retrieved during total hip arthroplasty. 217 87

1. Catecholamines, adenosine, gonadotrophins, vasoactive intestinal peptide (VIP) and E-series prostaglandins all elicit K+ currents in follicle-enclosed Xenopus oocytes. Evidence suggests that cyclic nucleotides act as intracellular messengers in the activation of this K+ conductance. Muscarinic agonists and some divalent cations (e.g. Co2+, Mn2+, Ni2+ and Cd2+) elicit slow oscillatory Cl- currents, which are activated through hydrolysis of inositol phospholipids and mobilization of intracellular calcium by inositol phosphates. 2. We investigated whether these membrane current responses were generated in the oocyte itself or in enveloping follicular cells which are coupled to the oocyte by gap junctions. Oocytes were defolliculated, either enzymatically using collagenase, or by manual dissection combined with rolling over poly-L-lysine-coated slides. Removal of follicular cells was checked using scanning electron microscopy. Membrane current responses of defolliculated oocytes were compared with responses seen in follicle-enclosed oocytes taken from the same ovary. 3. The K+ responses evoked by all the various hormones/neurotransmitters were either drastically reduced (greater than 90%) or abolished by defolliculation. K+ currents generated by the adenylate cyclase activator forskolin and by intraoocyte injection of adenosine 3',5'-cyclic monophosphate (cyclic AMP), or guanosine 3',5'-cyclic monophosphate were similarly reduced in defolliculated oocytes. In contrast, oscillatory Cl- currents to acetylcholine and divalent cations were selectively preserved through defolliculation. 4. Injection of cyclic AMP (1-20 pmol) into defolliculated oocytes had little or no effect on oscillatory Cl- currents elicited by ACh. However, the calcium-dependent transient Cl- current, activated by depolarization of the oocyte membrane, was consistently potentiated (100-900%) by injections of cyclic AMP (1-10 pmol). 5. These experiments suggest that cyclic nucleotide-activated K+ currents arise essentially in follicular cells and are monitored within the oocyte through electrical coupling by gap junctions. Oscillatory Cl- responses evoked by ACh and divalent cations are produced largely or wholly in the oocyte itself.
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PMID:Effects of defolliculation on membrane current responses of Xenopus oocytes. 255 77

A. niger LCF 9 synthesizes a new aspergillopeptidase of potential interest in therapeutics. The properties and operating range of the enzyme were determined. It is a semi-alkaline aspergillopeptidase (EC 3.4.23.4) with one endopeptidase activity. Its pI is 4.10, its molecular weight is 21000 Da and its A1%(1 cm) at 280 nm is 9.75. It rapidly hydrolyzes casein and hemoglobin. Its optimal pH is 7.8 and optimal temperature is 45 degrees C. It is thermally labile above 40 degrees C but can be stabilized by adding calcium ions. It is inhibited by phenylmethylsulfonyl fluoride (PMSF), by ethylenediaminetetraacetic acid (EDTA) and by certain metals ions, e.g. copper, manganese and cobalt ions. It has no dipeptidase or tripeptidase activity and its esterase activity is weak. It has a high collagenase activity and is to our knowledge the only aspergillopeptidase that is active towards benzoyl-arginine p-nitroanilide (BAPNA).
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PMID:Properties of a new alkaline proteinase from Aspergillus niger. 269 84

Matrix vesicles are present in the calcifying front and in the site of callus formation of fracture heeling. In calcifying process, matrix vesicles have important roles. The metalloprotease was isolated from matrix vesicles and subsequently characterized. Matrix vesicles obtained from chicken epiphysial cartilage by collagenase digestion and differential centrifugation were further purified by Sepharose CL2B gel filtration. The protease was solubilized from the vesicles and isolated by Sephadex G-150 gel filtration. Disc electrophoresis of the enzyme gave a single protein band. The matrix vesicle protease had a MW of 33,000 daltons, an optimal pH of 7.2, and was inhibited 100% by 0.1 mM EDTA and 0.2 mM o-Phenanthroline. alpha 2-Macroglobulin, ovalbumin, cysteine, penicillamine, ethane-1-hydroxy-1, 1-diphosphonate (EHDP) and pyrophosphate at higher concentrations were also inhibitory. The inhibition by o-phenanthroline was reversed by Co2+, Zn2+, Fe2+ and Cu2+. The protease released from the matrix vesicle at the calcifying front could degrade non-collagenous protein moieties which inhibit precipitation of minerals in the extra-vesicular matrix and thus facilitate mineralization.
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PMID:[Isolation and characterization of a metalloprotease associated with chicken epiphyseal cartilage matrix vesicles]. 309 Jan 76

A small metalloproteinase that digests Azocoll was found in the uterus of the rat. Its activity increased to high levels during the postpartum period in parallel with the breakdown of the extracellular matrix exclusive of collagen (Sellers, A., and Woessner, J.F., Jr. (1980) Biochem. J. 189, 521-531). This enzyme has now been purified almost 7,000-fold to homogeneity from 12 g of tissue using molecular sieve chromatography, blue sepharose chromatography, and zinc-chelate chromatography. Gel electrophoresis with sodium dodecyl sulfate and dithiothreitol gives Mr = 28,000 for the latent form of the enzyme and Mr = 19,000 for the active form that arises spontaneously or by treatment with aminophenylmercuric acetate. The enzyme digests components of the extracellular matrix including gelatins of types I, III, IV, and V, fibronectin, and proteoglycan. It digests the alpha 2(I) chain of gelatin in preference to the alpha 1(I) chain and cleaves dinitrophenyl-Pro-Leu-Gly-Ile-Ala-Gly-Pro-D-Arg. It cleaves the B chain of insulin at two points: Ala14-Leu15 and Tyr16-Leu17. It has no action on collagens of types I, III, IV, or V at 26 degrees C and no action on elastin or phenylazo-Pro-Leu-Gly-Pro-D-Arg. The pH optimum is at pH 7 and the pI at 5.9. The enzyme requires zinc and calcium ions for activity; cobalt and strontium can partially replace these metal ions. The enzyme is not inhibited by low levels of phosphoramidon or Zincov. Its properties clearly distinguish it from collagenase, gelatinase (matrix metalloproteinase 2), and stromelysin (matrix metalloproteinase 3); it therefore constitutes a further member of the family of extracellular matrix metalloendopeptidases. The name matrix metalloproteinase 7 is proposed.
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PMID:Purification and properties of a small latent matrix metalloproteinase of the rat uterus. 318 22

A metalloprotease has been isolated from matrix vesicles of chicken epiphyseal cartilage and subsequently characterized. Matrix vesicles obtained by collagenase digestion and differential centrifugation were further purified by Sepharose CL2B gel filtration. The protease was solubilized from the vesicles by treatment with deoxycholate and freeze-thawing, and then isolated by Sephadex G150 gel filtration. Disc electrophoresis of the enzyme, which displayed protease activity toward azocasein substrate, gave a single protein band. Based on molecular weight (MW) determination, lack of immunocross reactivity, and differences in electrophoretic migration, there is little possibility of any contamination with external protease from the commercial collagenase used for vesicle preparation. The matrix vesicle protease had a MW of 33,000 and a pH optimum of 7.2 and was completely inhibited by 0.1 mM EDTA and 0.2 mM o-phenanthroline. alpha 2-Macroglobulin, ovalbumin, cysteine, penicillamine, ethane-1-hydroxy-1, 1-diphosphonate (EHDP) and pyrophosphate at higher concentrations were also inhibitory. The inhibition by omicron-phenanthroline was reversed by Co2+, Zn2+, Fe2+, and Cu2+. Protease activity was most abundant in the heavy fraction of matrix vesicles fractionated by discontinuous sucrose density gradient centrifugation. Release of this protease at the calcifying front could degrade noncollagenous protein moieties that inhibit precipitation of minerals in the extravesicular matrix and thus facilitate mineralization.
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PMID:Isolation and characterization of a metalloprotease associated with chicken epiphyseal cartilage matrix vesicles. 352 86

The metabolism of saturated nitriles, including acetonitrile, has been assumed to occur by a cytochrome P-450-dependent oxidation at the alpha-carbon, yielding a cyanohydrin intermediate which may spontaneously degrade to hydrogen cyanide and an aldehyde. However, results of studies in our laboratory suggest that formaldehyde is not a metabolite of acetonitrile. Since acetonitrile is structurally similar to iodomethane, a substrate for glutathione (GSH) S-transferases, we hypothesized that the metabolism of acetonitrile to cyanide might also occur by a nucleophilic substitution reaction involving GSH. The present studies were conducted to investigate these hypotheses and to further our study of the effects of acetone on acetonitrile metabolism. Female Sprague-Dawley rats were pretreated with buthionine sulfoximine BSO (4 mmol/kg ip, at -4 and -2 hr), cobalt heme (90 mumol/kg sc, at -48 hr), acetone (1960 mg/kg po, at -24 hr), or vehicle, and hepatocytes were isolated after collagenase perfusion of the liver. BSO reduced the cellular GSH content by greater than 80%, but did not appear to affect the metabolism of acetonitrile: the liberation of cyanide correlated with cytochrome P-450, and not GSH, concentrations. Cobalt heme depleted hepatocellular cytochrome P-450 (-45%) content, decreased cell yield and viability, and resulted in a marked reduction in the metabolism of acetonitrile to cyanide. Cobalt heme did not affect the recovery of sodium cyanide from hepatocyte suspensions. Pretreatment of rats with acetone resulted in a twofold increase in the metabolism of acetonitrile to cyanide. Addition of acetone in vitro inhibited acetonitrile metabolism, with an IC50 of 319 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The metabolism of acetonitrile to cyanide by isolated rat hepatocytes. 355 37

Regulation of somatostatin (SS) secretion was studied in an in vitro system using collagenase-dispersed cells from fetal rat hypothalamus maintained in long term monolayer culture. Cultured cells exhibit a measurable basal secretion of immunoactive SS (SSLI) which can be augmented by carbachol, acetylcholine, or oxotremorine. The EC50 for carbachol is about 1 microM. Atropine, but not hexamethonium, antagonizes the action of cholinergic agonists. Cobalt or tetrodotoxin pretreatment diminishes basal secretion and eliminates the response to carbachol. Serotonin, several serotonin agonists, and gamma-aminobutyric acid (GABA) suppress carbachol-induced secretion. The GABA blockers bicuculline or picrotoxinin reverse the effect of added GABA and by themselves also augment SSLI secretion. Picrotin is inactive. The direct response to either bicuiculline or picrotoxinin is prevented by cobalt or tetrodotoxin treatment. These observations are consistent with the presence of a muscarinic cholinergic receptor which acts by a mechanism depending on an action potential and calcium influx to enhance the release of SSLI from neurosecretory cells. The data also support the conclusion that GABAergic transmission occurs within the cultures to tonically inhibit SSLI secretion. GABAergic, cholinergic, and serotoninergic systems may thus interact at the level of the hypothalamus to modulate SS secretion in vivo and thereby influence anterior pituitary release of GH and TSH.
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PMID:Muscarinic cholinergic stimulation of somatostatin secretion from long term dispersed cell cultures of fetal rat hypothalamus: inhibition by gamma-aminobutyric acid and serotonin. 612 32


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