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)

Two different subendothelial macromolecules have been identified as being thrombogenic: collagen and the microfibrils associated with elastin. The interaction between platelets and collagen involves the binding of platelet membrane receptors by numerous sites repeatedly staggered along a collagen fiber: this explains why the preservation of ordered structures (quaternary and tertiary structures) is so important in the reactivity of collagen towards platelets. In the case of Type III collagen, a nonapeptide has been identified as possibly being part of these repetitive sites. The microfibrils have not yet been characterized, although the biochemical data presently available show that they are acidic glycoproteins resistant to collagenase. Microfibrils extracted from human placenta or bovine aorta induce the aggregation of platelets in a reaction which involves platelet glycoprotein Ib and FVIII/vWF. A general model proposed for explaining platelet adhesion to subendothelium suggests that two different mechanisms should be envisaged depending on the thrombogenic macromolecules (collagen, microfibrils) involved.
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PMID:The molecular interaction between platelet and vascular wall. 622 98

Bovine medial explants in culture synthesize a potent inhibitor of mammalian collagenase but not of bacterial collagenase. This inhibitor has been partially purified and has an apparent molecular weight of 45,000. It is a glycoprotein and is stable to heat, trypsin, acid and mercurials. Inhibitory activity is destroyed on reductive alkylation. The inhibitor interacts with collagenase and this interaction leads to the loss of enzymatic activity. This inhibitor may play a physiological role in the control of collagen degradation in blood vessels.
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PMID:Purification and properties of a collagenase inhibitor from cultures of bovine aorta. 624 63

The steroidogenic properties of a glycoprotein fraction (ASF), isolated from normal human urine, were studied in cat adrenal capsular collagenase-dispersed cells and its effects compared to those of ACTH and Angiotensin II (AII). ACTH, AII and ASF induced dose-related increases in both aldosterone and cortisol production. In order of potency, ACTH = AII greater than ASF in stimulating aldosterone production and ACTH greater than AII greater than ASF in stimulating cortisol production. Increases in cAMP accompanied the steroidogenic response to ACTH but not to AII or ASF. The response to AII, but not to ASF, was inhibited (87% of normal) by equimolar concentrations of [Sar1, Thr8]AII, a specific AII antagonist. These results suggest that ASF is a true aldosterone secretagogue and that it initiates steroidogenesis by mechanisms similar to those of AII. However, the inability to block it effect with a specific antagonist of AII provides evidence for its action on a separate receptor site.
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PMID:In vitro steroidogenic properties of a new hypertension-producing compound isolated from normal human urine. 624 62

An hypothesis regarding the pathogenesis of amyotrophic lateral sclerosis is presented, which places emphasis on extraneural cells. Classical experimental denervation is compared and contrasted with motor neuron disease, both from information in the literature as well as concepts deriving from the hypothesis. Background information regarding neuromuscular junction-specific (16S) acetylcholinesterase and a basal lamina-enriched surface glycoprotein (fibronectin) are presented, which suggest not only their mutual interaction, but likely parallel regulation on muscle cell surfaces by the motor nerve. Since 16S acetylcholinesterase likely contains basal lamina-type collagen and fibronectin specifically associates with collagen, a model relating activation of latent collagenase enzyme in amyotrophic lateral sclerosis is described. It is suggested that continued degeneration, including transneuronal effects, of the motor system ensues from random, continuous loss of nerve-muscle adherence resulting from collagen resorption at the neuromuscular junction.
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PMID:Neuromuscular junction macromolecules in the pathogenesis of amyotrophic leteral sclerosis. 624 44

An inhibitor of mammalian collagenase has been partially purified from the spent medium of smooth muscle cells grown in culture. The inhibitor is a glycoprotein with an apparent molecular weight of 25,000. It is stable to heat, acid, and mercurials, but is destroyed by trypsin treatment and by reductive alkylation. The inhibitor interacts with active mammalian collagenase and this interaction results in the loss of enzymatic activity. This presumptive collagenase-inhibitor complex is stable to the treatment with mercurials and to trypsin. These latter observations suggest that this inhibitor is different from other collagenase inhibitors that are thought to be responsible for the latency of the enzyme.
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PMID:Properties of a collagenase inhibitor partially purified from cultures of smooth muscle cells. 625 11

Glycoproteins from bovine aorta intima were isolated by a sequential digestion of the tissue with collagenase and elastase after extration of the tissue with saline. The proteins in the extracts were precipitated by (NH4)2SO4 and fractionated by Con-A sepharose affinity chromatography. The fractions were analyzed for their carbohydrate composition and by polyacrylamide disc gel electrophoresis. These studies show that considerable heterogeneity of aorta glycoproteins exists. Some of the glycoprotein materials are likely intimately associated with fibrous structures, collagen and elastin, of the aorta intima.
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PMID:Studies of glycoproteins from bovine aorta. 625 71

A neutral protease with a marked specificity for gelatin as a protein substrate has been purified to homogeneity from medium of human skin in serum-free explant culture. The pH optimum of this gelatinase is between 7.0 and 7.5 with little or no activity displayed below pH 5. Inhibition by EDTA, ethylene glycol bis(beta-amino-ethyl ether)N,N,N',N'-tetraacetic acid (EGTA), and 1,10-phenanthroline suggest that the enzyme is a metalloendopeptidase. Calcium concentration-dependent inhibition of the enzyme by EGTA and EDTA suggest further that there is a requirement for extrinsic calcium. Indeed, removal of calcium and reduces enzyme activity, and subsequent addition of calcium restores full activity. The gelatinase is not inhibited by serine protease inhibitors but is inhibited by cysteine, dithiothreitol, and beta-mercaptoethanol. It is also inhibited by a macromolecular inhibitor of collagenase which has been purified from human skin fibroblasts. The apparent molecular weight of this enzyme, as determined by gel filtration is 120,000-150,000. The enzyme is a glycoprotein, as indicated by staining with periodic acid-Schiff reagent and by its affinity for lectins. Human skin gelatinase shows little or no reactivity toward common protein substrates, such as hemoglobin or casein, and does not cleave helical collagen. Two sites of cleavage in the sequence of gelatin, Gly-Ile and Gly-Leu, have been positively identified using synthetic substrates and tryptic peptides of collagen.
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PMID:Purification and properties of a gelatin-specific neutral protease from human skin. 626 Aug 9

The steroidogenic properties of a glycoprotein fraction (urinary ASF), isolated from normal human urine, were studied in collagenase-dispersed rabbit adrenal capsular cells in 1) define the requirements for its steroidogenic activity, and 2) assess its site and mode of action. When incubated with adrenal cell suspension at 37 degrees C for 2 hours, urinary ASF induced dose-related increases in both aldosterone and corticosterone production. However, urinary ASF was less potent (ED50 = 10(-9) M) than either angiotensin II (ED50 = 8 x 10(-11) M) or ACTH (ED50 = 4 x 10(-11) M). Increases in cyclic AMP accompanized the steroidogenic response to ACTH but not to either urinary ASF or AII. Deprivation of potassium in incubation media or the addition of ouabain (1 mM) during incubation completely inhibited the steroidogenic response to either urinary ASF, ACTH, or AII. Like ACTH and AII, urinary ASF increased conversion of corticosterone to aldosterone. Specific competitive antagonist of AII (Sar1, Thr8, AII) and ACTH ([I1e9]ACTH1-24) did not prevent the ASF-induced increase in aldosterone production. These results suggest that urinary ASF is readily distinguishable from ACTH. Although it shares similar steroidogenic properties with AII, the inability of AII antagonist to block its effects suggests that it acts at a separate receptor site.
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PMID:Steroidogenic characteristics of a new aldosterone-stimulating factor (ASF) isolated from normal human urine. 626 51

1. Cell cultures propagated from foetal bovine ligamentum nuchae synthesized and secreted two glycoproteins, designated MFP I and MFP II, that are closely related to elastic-fibre microfibrils. Glycoproteins MFP I (apparent mol.wt. 150 000) and MFP II (apparent mol.wt. 300 000) were metabolically labelled, separated from other culture-medium components by immunoprecipitation with a specific anti-(microfibrillar protein) serum, and analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and sodium dodecyl sulphate/gel-filtration chromatography. 2. Ligament cells also synthesized and secreted fibronectin, but salt-fractionation and immunoprecipitation studies with a specific anti-(cold-insoluble globulin) serum established that neither glycoprotein MFP I nor glycoprotein MFP II was related to fibronectin. 3. The secretion of glycoprotein MFP I, but not that of glycoprotein MFP II, was enhanced by the addition of ascorbate to the culture medium. 4. Ascorbate-supplemented ligament cells incorporated [3H]proline into glycoprotein MFP I, and 36% of the nondiffusible proline residues were hydroxylated, exclusively as 4-hydroxy[3H]proline. Less than 1% of the total proline residues in [3H]proline-labelled glycoprotein MFP II were hydroxylated. 5. Ascorbate-supplemented cells incorporated [14C]lysine into glycoprotein MFP I and 30% of the non-diffusible lysine residues were hydroxylated. 6. Newly secreted glycoprotein MFP I was digested by highly purified bacterial collagenase to yield polypeptide fragments of apparent mol.wts. 50 000 and 30 000. Glycoprotein MFP II was not digested by bacterial collagenase. 7. The results suggest that elastic-fibre microfibrils are composed of a novel collagenous glycoprotein MFP I in association, as yet undefined, with a non-collagenous glycoprotein MFP II.
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PMID:The nature of the microfibrillar glycoproteins of elastic fibres. A biosynthetic study. 627 35

The interaction of human blood platelets with collagenase-treated rabbit subendothelium was studied by histochemical ultrastructural methods and by morphometric semi-quantitative analysis. Aortas were deendothelialized and incubated: 1) with a highly purified bacterial collagenase whose specificity was controlled; and 2) with the same collagenase followed by chymotrypsin. For histochemical studies, tannic acid, ruthenium red, and peroxidase-labeled Ricinus communis and concanavalin A were used. Electron microscopy showed that after digestion of fibrillar collagen by collagenase, adherent and aggregated platelets were observed on Ricinus communis-, concanavalin A-, and ruthenium red-positive glycoprotein microfibrils. After successive incubation with collagenase and chymotrypsin, the microfibrils disappeared. No platelets were observed on the remnant amorphous elastin. Morphometric analysis confirmed the interaction of platelets with collagenase-treated subendothelium. In addition, glycoproteins were extracted from collagenase-treated rabbit aortas using 5 M guanidine. Using an in vitro quantitative test, significant platelet adhesion to these glycoproteins was observed. Our results show an interaction between platelets and noncollagenic glycoprotein microfibrils.
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PMID:Histochemical and ultrastructural characterization of subendothelial glycoprotein microfibrils interacting with platelets. 627 53


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