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)

A small molecular weight structural glycopeptide was solubilized after collagenase digestion of the connective tissue capsule surrounding the 5-day sponge-implant of the rat. The major amino acids are one residue each of aspartic and glutamic acids, proline, hydroxyproline and alanine and two residues of glycine, and the carbohydrates are one residue each of glucose, xylose and hexosamine and two residues of mannose. The sum of the amino acid and carbohydrate residues gives a molecular weight of 1635. Dansylation of the glycopeptide produces a single strongly fluorescent yellow-orange amino-terminal spot, not positively identified. The solubilization of the granuloma glycopeptide by collagenase and its composition are suggestive of its association with an immature form of collagen in early granulation tissue.
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PMID:Isolation and purification of a small molecular weight hydroxyproline-containing structural glycopeptide from early mammalian granulation tissue. 14 81

The carbohydrate chains present in the tubular basement membrane of bovine kidney were studied. Digestion with collagenase followed with pronase resulted in a complete solubilization of the basement membrane. The different glycopeptides were purified by gel filtration and ion-exchange chromatography. Two kinds of carbohydrate chains could be characterized: oligosaccharides composed of glucosamine, mannose, galactose, fucose and sialic acid, and glucosylgalactose disaccharides. A very small portion of the oligosaccharide chains (ca. 4%) appeared to be free of sialic acid. The bulk of these chains contained sialic acid and fucose, although in small amounts. Only traces of galactosamine were found.
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PMID:Epithelial basement membrane of bovine renal tubuli. Isolation and analysis of the carbohydrate chains. 17 41

Hydroxyproline-containing structural glycopeptide fractions were isolated from collagenase-digested neutral salt-insoluble collagen of five-day sponge-implant connective tissue of the rat. The glycopeptide fractions characterized migrate as a single, strongly anionic band on disc gel electrophoresis at pH 9.5, are eluted on gel filtration as a small molecular weight peak, approximately 2000, and are resolved into thirteen glycopeptide fractions by DEAE-cellulose chromatography. Amino acid analyses of some of these fractions indicate a similarity in composition, the principal ones being aspartic and glutamic acids, serine, glycine, alanine, valine, proline and hydroxyproline. Three neutral carbohydrates, glucose, mannose and xylose, in different relative proportions and hexosamine are also present in the fractions. Amino-terminal amino acid determinations indicate a microheterogeneity of the glycopeptides. The electrophoretic behaviour and non-diffusibility of the small molecular weight glycopeptides suggest an intimate association between acidic hydroxyproline-containing peptides and carbohydrate components of developing connective tissue.
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PMID:Hydroxyproline-containing structural glycopeptide fractions from subacute inflammation connective tissue. 17 78

The effects of various sugars on the simultaneous release of insulin and accumulation of cyclic AMP were studied in collagenase isolated rat pancreatic islets. D-Glucose stimulated the formation of cyclic AMP at 3 and 60 min of incubation, whether measured by a label incorporation technique, or by the protein kinase binding assay of Gilman. Only D-glucose and D-mannose were able to stimulate insulin release and cyclic [3H]AMP accumulation in the absence of other substrate. D-fructose had a stimulatory effect in the presence of 3.3 mM D-glucose only at a high concentration (33.8 mM), and enhanced the effects of 8.3 mM glucose when added at the concentration of 8.3 mM. D-Galactose was effective only together with 8.3 mM D-glucose. The order of potency of these hexoses, both regarding insulin secretion and cyclic [3H]AMP accumulation, was glucose-mannose-fructose-galactose. L-Glucose and 3-O-methylglucose had no effects at 60 min when incubated together with 8.3 mM D-glucose, whereas at 3 min, 3-O-methylglucose induced a small stimulation of the cyclic [3H]AMP response. D-mannoheptulose and D-glucosamine inhibited the insulin and cyclic [3H]AMP responses to 27.7 mM glucose. Mannoheptulose suppressed completely the glucose effect on cyclic nucleotide accumulation within 90 s. Although under all incubation conditions, the threshold stimulatory or inhibitory concentration of a given agent was identical for insulin release and cyclic [3H]AMP accumulation, these two variables showed quantitative differences in incubations of 60 min, the magnitude of the changes in insulin secretion being larger than that for the cyclic nucleotide. It is suggested that modulation of islet cyclic AMP level is an important step in the transmission of the effect of various sugars on insulin release; however, glucose and possibly other sugars may also enhance insulin release by additional mechanisms not involving the adenylate cyclase-cyclic AMP system of the beta-cell.
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PMID:Effect of hexoses and mannoheptulose on cyclic AMP accumulation and insulin secretion in rat pancreatic islets. 18 Oct 79

Standardization of a technic for isolating large numbers of pancreatic islets is described. This procedure employed collagenase digestion of rat pancreatic tissue in a cylindrical wire screen in order to separate isolated islets from undigested pancreas. From this basic protocol the following conditions were established: (1) the duration of the initial digestion period was found to be optimal at six minutes; (2) three subsequent digestions of one minute each effected maximum islet yield; (3) the optimal initial collagenase concentration was found to be 1,000 U. (Worthington)/ml.; and (4) proper reductions of collagenase concentrations during the three subsequent digestions were found to be 50 per cent of each preceding incubation period. This method, combined with Ficoll gradient separation, yielded a mean of 800 islets per two rat pancreases. The isolated islets appeared morphologically intact, contained 0.36 +/- 0.05 mug. protein/islet, and demonstrated a normal biphasic release of insulin in response to stimulative levels of D-glucose. The present method provides a means for obtaining a large mass of viable islet cell tissue in a short time.
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PMID:Standardization fo a digestion-filtration method for isolation of pancreatic islets. 18 6

The uptake of 45Ca2+ by a lanthanum-non-displaceable pool in pancreatic islets was studied; Raising the extracellular D-glucose concentration from 3 to 20 mM stimulated the 45Ca2+ uptake in hand-dissected islets of ob/bo-mice as well as in collagenase-isolated islets of ob/ob or normal mice. The effect was dose-dependent in the range of 0-20 mM D-glucose and was seen throughout a wide range of extracellular calcium concentrations (16 mumol-2.56 mmol of Ca2+ added per litre of medium). The 45Ca2+ uptake was also enhanced by other known insulin secretagogues (D-mannose, L-leucine, tolbutamide) and was uninfluenced by compounds lacking insulin-releasing capacity (3-O-methyl-D-glucose, L-glucose, D-galactose, D-leucine). The stimulatory effect of D-glucose was blocked by inhibitors of glucose-induced insulin release (D-mannoheptulose, diazoxide, L-adrenaline). The results support the view that the lanthanum-nondisplaceable calcium pool is related to the insulin-releasing mechanism, although the exact nature of this relationship is still unclear.
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PMID:Effects of various modifiers of insulin release on the lanthanum-nondisplaceable 45Ca2+ uptake by isolated pancreatic islets. 19 76

Glucose-induced insulin secretion is enhanced by a preceeding glucose stimulus. The characteristics of this action of glucose were investigated in perfused pancreas and collagenase-isolated islets of Langerhans. A 20- to 30-min pulse of 27.7 mM glucose enhanced both the first and second phase of insulin release in response to a second glucose stimulus by 76-201%. This enhancement was apparent as an augmented maximal insulin release response to glucose. The effect of priming with glucose was seen irrespective of whether the pancreatic tissue was obtained from fed or fasted rats. Separating the two pulses of hexose by a 60-min time interval of exposure to 3.3 mM glucose did not abolish the potentiation of the second pulse. Omission of Ca(++) as well as the inclusion of somatostatin or mannoheptulose during the first pulse abolished insulin secretion during this time period; however, only the inclusion of mannoheptulose deleted the potentiation of the second pulse. d-Glyceraldehyde, but not pyruvate, d-galactose, or 3-isobutyl-1-methylxanthine, could substitute for glucose in inducing potentiation. In islets labeled with [2-(3)H]adenine, the [(3)H]cyclic AMP response to glucose was increased by 35% when measured after 1 min, but was increased only marginally after 2-10 min of stimulation with a second pulse of glucose. The production of (3)H(2)O from glucose was not affected by glucose priming. It is concluded that (a) the induction of the glucose-induced, time-dependent potentiation described here is dependent on glucose metabolism but not on stimulation of cyclic AMP, calcium fluxes, or insulin release per se; (b) the mechanisms that mediate the pancreatic "memory" for glucose are unknown but do not seem to involve to a major extent an increased activity of the adenylate cyclase-cyclic AMP system of the beta-cell; (c) the evidence presented supports the hypothesis of a dual role of glucose for insulin release.
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PMID:Immediate and time-dependent effects of glucose on insulin release from rat pancreatic tissue. Evidence for different mechanisms of action. 20 21

Fluxes of 86Rb+ and hydrolysis of p-nitrophenyl phosphate were measured in collagenase-isolated islets of diabetic C57BL/KsJ-db/db-mice and normal controls (C57BL/KsJ-+/+). Both types of islets accumulated Rb+ avidly, as originally reported for hand-dissected islets of non-inbred ob/ob-mice. KsJ-db/db-mouse islets showed enhanced accumulation of Rb+ and normal activity of K+-activated nitrophenyl phosphatase. D-glucose, 20 mmol/l, inhibited Rb+ efflux in normal islets but not in those from KsJ-db/db-mice. The glucose insensitivity of Rb+ efflux was observed in young animals, which exhibit glucose-induced insulin release, as well as in old animals, which do not secrete insulin in response to glucose. The anomalous regulation of Rb+ efflux already present in young animals may bear on the liability of KsJ-db/db-mouse B-cells to develop defective control of membrane potential, an abnormal metabolism of cyclic AMP, and a marked failure of insulin secretory capacity.
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PMID:86Rb+ fluxes and K+-stimulated nitrophenyl phosphatase activity in the pancreatic islets of genetically diabetic mice (C57BL/KsJ-db/db). 21 36

Solubilization of the normal glomerular basement membrane with various solvents revealed that the material is held together by hydrogen and disulfide linkages as well as ionic salt bridges which ionize at around pH 10.0. Pronase digestion indicated that differences in susceptibility to enzyme digestion exist between normal and nephritic membrane. Titration of a urea-insoluble material indicated that some alteration must have taken place in the association between various components of the nephritic basement membrane. Chemical analysis of alkali-solubilized fractions suggested that greater alkali susceptibility of the nephritic material may be present. A collagen-like material resembling both tendon and dog basement membrane collagen in its amino acid composition was isolated. It contained 10% hexose, but in addition to glucose and galactose, mannose was also detected. A glycopeptide fraction obtained by pronase and collagenase digestion has a carbohydrate composition similar to the collagen-like material above. These substances probably represent incompletely digested fragments of the basement membrane.
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PMID:Studies of normal and nephritic rat glomerular basement membrane. 23 74

A subpopulation (n = 27) of normoglycaemic Sand rats was characterized as carbohydrate-intolerant by intraperitoneal glucose loading. Five of these animals did not show any rise in peripheral insulin concentrations when injected with glucose. However, when isolated by collagenase digestion their islets still exhibited a significant enhancement of insulin secretion in response to glucose, glyceraldehyde, mannose and theophylline. The in vitro secretory responses were comparable to those of islets from carbohydrate-tolerant Sand rats. The results underline the importance of the natural environment for the B-cell response in vivo.
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PMID:Apparent discrepancy between the insulin secretory responses in vivo and in vitro in carbohydrate-intolerant Sand rats. 39 3


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