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)

Neovascularization of developing, repairing or neoplastic tissues is regulated, at least partially, by a family of proteins of low molecular mass (1000 less than mol mass less than 50 000 Da) which can be extracted from avascular tissues, such as hyaline cartilage, aorta or bladder epithelium, by mild salt solutions. These extractable proteins, functionally defined as anti-invasion factor (AIF), act as local regulators for some of the major mechanistic pathways by which endothelial cells are thought to invade tissues during neovascularization, mainly by matrix-degrading enzymes and by increased rates of migration and proliferation. AIF contains a spectrum of proteinase (collagenase) inhibitory activities, as well as an endothelial cell growth inhibitor. The endothelial cell growth inhibitor is directed against actively dividing endothelial cells in culture but has no effect on endothelial cell monolayers or any other cell lines tested. In tumours, the AIF-derived endothelial cell growth inhibitor may limit tumour growth to less than 2 mm in diameter by inhibiting tumour neovascularization.
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PMID:Inhibition of neovascularization by a cartilage factor. 619 59

Collagen-like proteins have been found in the egg shell membranes of the hen. Materials similar to types I and V collagens were detected in each of the two layers of this membrane, the thick outer membrane and the thin inner membrane. Collagen was extracted by acid-pepsin digestion and isolated by differential salt precipitation. Identification of type-specific collagen-like material was established by coelectrophoresis on SDS-polyacrylamide gels using known collagen standards. These bands were susceptible to digestion by bacterial collagenase. From differential staining of the gels it was estimated that the ratio of collagen types I:V was approximately 100:1. Further confirmation of these biochemical results was obtained with immunofluorescence microscopy using type-specific antisera against chicken types I and V collagen with the indirect sandwich technique. Both the inner and outer shell membranes contained the two types of collagen. Within each membrane, the large, coarse 2.5-micron fibers contained predominantly type I collagen-like material, while type V collagen was mainly associated with the delicate narrower fibers of approximately 0.6-micron diameter. These tended to be concentrated in the inner membrane. At the electron microscopic level, both types of fibers were coated with glycoproteins that stained positively with ruthenium red. The deposition of these collagen-like substances by the hen oviduct on to the surface of the developing egg is an additional example of interstitial-type collagen synthesis and secretion by epithelial rather than by mesenchymal cells.
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PMID:Collagen in the egg shell membranes of the hen. 620 93

A procedure for dissociation of the nasal salt glands of the domestic duck, Anas platyrhynchos, into suspensions of individual cells has been developed. This technique employs enzymatic digestion with collagenase, hyaluronidase, and chymotrypsin; divalent cation chelation with EDTA; and gentle mechanical dispersion. Average cellular yields of 39 and 26% based on DNA recovered were obtained from the glands of freshwater- and saline-adapted ducks, respectively. Epithelial secretory cells comprised 60-80% of the cell suspensions with the remainder of the populations consisting of endothelial cells, fibroblasts, and blood cells. The dissociated cells were viable as judged by trypan blue exclusion (80-100%, maintenance of ultrastructural integrity, and retention of responsiveness to secretagogues and metabolic inhibitors. Methacholine chloride (0.5 mM) stimulated oxygen consumption by suspensions of both freshwater- and saline-adapted cells, whereas ouabain (0.05 mM) abolished the methacholine-stimulated respiratory response. These cell suspensions provide a promising system for the in vitro study of secretory mechanisms in the avian salt gland.
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PMID:Dissociation of avian salt gland: separation procedures and characterization of dissociated cells. 624 10

Type III collagen was prepared from human liver by limited pepsin digestion, differential salt precipitation, and carboxymethylcellulose chromatography. Ten distinct peptides were obtained by cyanogen bromide digestion. The peptide alpha 1 (III)-CB5 was further purified by carboxymethylcellulose chromatography, and its amino acid sequence was determined. Automatic Edman degradation of intact alpha 1 (III)-CB5, tryptic and thermolytic peptides, and hydroxylamine-derived fragments was used to establish the total sequence. The mammalian collagenase site contained in the alpha 1 (III)-CB5 sequence was ascertained by digestion of native type III collagen with purified rheumatoid synovial collagenase. Collagenase cleavage occurred at a single Gly--Ile bond, one triplet before the corresponding specific cleavage site of type I collagen. The present work brings the known sequence of human liver type III collagen to include alpha 1 (III)-CB3-7-6-1-8-10-2-4-5. These correspond to the homologous region of alpha 1 (I)-CB0-1-2-4-5-8-3-7 residues 11--804.
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PMID:Covalent structure of collagen: amino acid sequence of alpha 1 (III)-CB5 from type III collagen of human liver. 624 25

Regulation of respiration by catecholamines was studied in adipocytes isolated from interscapular brown adipose tissue of warm-acclimated rats by rapid digestion of collagenase. (-)-Norepinephrine stimulated adipocyte respiration 10-12 times above basal values in less than 3 min. (Vmax = 410 +/- 29.5 nmol O2 . min-1 . 10(-6) cells-1). Stimulated respiration remained stable for at least 20 min, provided that cells were incubated in balanced salt media containing bicarbonate. The maximal capacity of total brown adipose tissue for norepinephrine-stimulated respitarion was estimated at 1.5 ml O2/min per rat. beta-Adrenergic agonists increased calorigenesis stereospecifically with an order of potency expected for respiratory stimulation via adrenoceptors of the beta 1-subtype: (-)-isoproterenol (1/2 Vmax = 2 nM) greater than (-)-norepinephrine (1/2 Vmax = 20 nM) approximately equal to (-)-epinephrine (1/2 Vmax = 40 nM) greater than corresponding (+)-stereoisomers. The alpha-adrenergic agonist phenylephrine (1/2 Vmax = 5 microM) stimulated adipocyte respiration as rapidly and as effectively as beta-agonists. Although alpha-adrenoreceptors are present in brown adipose tissue, studies with alpha- and beta-adrenergic antagonists revealed that norepinephrine elicits thermogenesis at physiological concentrations (less than or equal to 1 microM) predominantely via beta 1-adrenergic pathways.
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PMID:Stereospecific stimulation of brown adipocyte respiration by catecholamines via beta 1-adrenoreceptors. 624 20

Collagenolytic activity was estimated in skin and joint cartilage of lathyritic rats by means of a biological assay. Lathyrism was induced by feeding beta-aminopropionitrile fumarate for six weeks, and the lathyritic state was confirmed by characteristic radiographic, histomorphologic and biochemical findings. Both tissues in lathyritic animals revealed significantly increased collagenolytic activity in comparison with those of the control animals. Studies were performed using ethylendiaminetetraactate and normal rat serum to determine the origin of inhibition of the collagenolytic system inhibition. Since both agents showed no inhibition of collagenolysis, the highly increased collagenolytic activity in lathyritic skin and joint cartilage appears not to be derived from polymorphonuclear cells nor from serum, but from the tissue itself. Elevation of collagenase activity may be important with respect to the increased neutral salt solubility of collagen and hydroxyproline excretion observed in experimental lathyrism.
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PMID:Collagenase activity of cartilage in rats with experimental lathyrism: a model of bone diseases. 625 68

The presence of collagenase bound to collagen extracted and purified from several animal and human sources by a standard procedure has been confirmed by different methods. Polyacrylamide (10%) gel electrophoresis at pH 8.1 of intact or "spontaneously"degraded neutral salt soluble collagen results in the separation of two components: the upper one says at the origin and represents collagen or collagen ragments, whereas the lower protein component contains no collagen, often preserves specific collagenolytic activity, and migrates as a single band in SDS/polyacrylamide electrophoresis. With lower polyacrylamide gel concentration the electrophoretic separation of the two components is less clear. Removal of the lower protein component from collagen solutions by two different methods (TCA-ethanol purification cycles and pepsin digestion) results in concomitant loss of their "spontaneous" instability. Eluates of the lower protein component stimulate the heterologous production of a monospecific antibody capable of inhibiting the collagenolytic activity of homologous crude collagenase preparations. It is suggested that collagen-bound collagenase is not an artifact of the extraction procedure but rather a physiological reality, probably corresponding in the living animal to the enzyme closely associated with extracellular collagen fibers, revealed by immunohistochemical methods.
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PMID:Collagen-bound collagenase. 625 23

Molecular forms of acetylcholinesterase (AChE) in fresh electric organ tissue are elongated structures in which a multisubunit head containing the catalytic sites is attached to a fibrous tail. The principal form, 18S AChE, is of MW ca. 1,100,000 and aggregates reversibly at low ionic strength. Trypsin converts it to an 11S globular tetramer devoid of the tail and lacking the capacity to aggregate reversibly in low salt. Amino acid analysis, collagenase and pepsin digestion and immunological techniques were utilized to demonstrate that the fibrous tail of the elongated forms of AChE is a collagen triple helix. The distal portion of the tail contains a region responsible for the capacity for aggregation at low ionic strength. This latter property may be related to the postulated role of the tail in anchoring AChE to the fibrillar matrix of the basal lamina.
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PMID:Electric eel acetylcholinesterase: a multisubunit enzyme containing a collagen tail. 626 36

The salt glands of control and salt-stressed ducklings were dissociated with collagenase to produce cell aggregates or 'minilobules' which were cultured. The fine-structural organization of freshly isolated and cultured (up to 72 h) aggregates were examined and showed surprisingly intact fine-structural organization with minimal changes from untreated glands. Incorporation of [3H]leucine into total protein, membrane protein and immunoprecipitable Na,K ATPase was determined in cultures at various time points, by pulse or pulse-chase experiments. Incorporation of label was linear for 4 h in protein, but higher in cultures of salt-stressed glands than in controls. Na,K ATPase was synthesized throughout the time of the experiment, the rate being highest during the first 4 h, reaching a plateau by 24 h. Up to 10% of the total label was present in Na,K ATPase. These results are discussed with reference to the use of minilobule culture to analyse further synthesis and assembly during biogenesis and control of these processes.
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PMID:Organotypic cultures of the avian salt gland: biosynthesis of membrane proteins. 626 44

We have extracted acetylcholinesterase from young chick retinas by homogenization in different solutions combining high salt concentration, ionic and nonionic detergents, and EDTA, looking for an optimum procedure for the solubilization of collagen-tailed, asymmetric structural forms of the enzyme. High salt and EDTA seem to be the only necessary requirements for the solubilization of acetylcholinesterase as the A12 form (20S), and the presence of detergent in the homogenization medium does not significantly improve the yield of tailed enzyme. Extraction in the absence of detergent has the potential advantage of a threefold enrichment of tailed enzyme, because only about one-third of the total retinal acetylcholinesterase activity is solubilized. Divalent cations, especially Ca2+, seem to be involved in the attachment of the tailed enzyme to the retinal membranes, at the tail level. High salt-EDTA-extracted 20S acetylcholinesterase (without detergent) aggregates in the presence of exogenous Ca2+ and becomes "insoluble." However, the aggregated 20S acetylcholinesterase can be completely recovered and brought back into solution by further addition of EDTA. Besides, the aggregation can be prevented by the inclusion of Triton X-100 in the homogenization buffer or by adding the detergent concurrently with Ca2+. It is postulated that the acetylcholinesterase collagenous tail is coated by acidic lipid molecules hydrophobically bound to the tail protein so that Ca2+ ionic bridges would actually link these lipid molecules (and consequently the tail) to the membrane matrix. Removal of the lipid coat (e.g., by Triton X-100) produces tailed acetylcholinesterase molecules that no longer aggregate in the presence of Ca2+ and are fully accessible to collagenase digestion.
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PMID:Solubilization of collagen-tailed acetylcholinesterase from chick retina: effect of different extraction procedures. 627 24


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