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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)

Only one collagenase (EC 3.4.24.3) is produced by the non-pathogenic Achromobacter iophagus strain. The chromatography of the crude enzyme on DE-32 cellulose followed by gel filtration on Sephadex G-100 in the presence of 1 M sodium chloride led to the isolation of a homogeneous enzyme. Its specific activity (1.642 mukat/mg) represents the highest value ever obtained for a bacterial collagenase. The amino acid composition of A. iophagus collagenase differs from that of Clostridium histolyticum mainly in the sulfur-containing amino acids. 1 mol of zinc was found for 1 mol of enzyme of molecular weight 104 000. The autodegradation of the A. iophagus collagenase results in the formation of at least three active fractions which can be separated by preparative polyacrylamide gel electrophoresis as well as rechromatography on DE-32 cellulose. They are active towards the synthetic substrate as well as towards the native collagen. The results of ORD have shown that the digestion of the last one occurs in the helical parts of the substrate.
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PMID:Chemical characterization and study of the autodigestion of pure collagenase from Achromobacter iophagus. 17 67

After incubation of isolated forelimb regenerates of Notophthalmus (Triturus) viridescens at all developmental stages for 60 minutes at 37 degrees C in a salt medium containing 111 mM sodium chloride, 5.6 mM potassium chloride and 100 mM sodium phosphate buffer at pH 7.5, the wound epithelium of each regenerate was removed intact from its underlying mesenchymal component. The suggestion is made that the salt medium is an effective epithelial-mesenchymal separating agent due to a combination of its hypertonicity, high ionic strength and the fact that the medium precipitates calcium as calcium phosphate. Attempts to dissect away the epithelium from the mesenchyme after incubation of isolated regenerates in sodium phosphate containing 1% or 3% Difco 1:250 trypsin, 10 mM EDTA or 150 units collagenase/ml medium were unsuccessful. Epidermis of adult newt forelimb skin was removed only after extended incubation of the forelimbs in the salt medium for three hours at 37 degrees C or after freezing isolated forelimbs in buffer and subsequent thawing.
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PMID:Separation of the epithelial and mesenchymal components of the newt limb regenerate with salt. 49 Jan 37

We investigated the steroid biosynthetic capabilities of ovarian granulosa and thecal elements of the viviparous dogfish, Squalus acanthias. In this report we present evidence that granulosa cells secrete quantitatively important amounts of progesterone (P), testosterone (T), and estradiol-17 beta (E), while theca has a more limited capacity to synthesize T and E. Ovarian granulosa cells were obtained from animals at each stage of gestation. After collagenase dispersion, an aliquot of 250,000 cells was incubated at 18 degrees C in basal medium, containing Eagle's salts, glutamine, penicillin, streptomycin and adjusted with 136 mM sodium chloride and 350 mM urea. After a 4 hour incubation, the content of P, T, and E in medium was determined by radioimmunoassay. P was not detectable at any time, while E was present throughout the cycle, being maximal when gestation is three quarters complete (Stage C). T gradually increased from Stage B toward late pregnancy. In Stage C granulosa cells, E production increased in the presence of graded doses of T substrate. Also, a homologous pituitary extract (1/25 equivalents) and the calcium ionophore A23187 stimulated production of all 3 steroids. Using radioisotopes, granulosa cells showed a wide range of synthetic capacities. In Stage C thecal tissue, E production also increased in the presence of graded doses of T substrate, while pituitary extract only increased T. When granulosa and theca were recombined, in the presence of pituitary extract, P levels decreased with a corresponding increase in T, when compared to granulosa alone. These data suggest a possible interaction between granulosa and theca for steroid biosynthesis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of ovarian steroidogenesis in vitro in the viviparous shark, Squalus acanthias. 172 88

Collagen biomaterials should be cross-linked in order to prevent biodegradation when they are used as implants. We have compared the cross-linking efficiencies of glutaraldehyde and acyl azide in pericardium. Glutaraldehyde is used currently, but it elicits a cytotoxic effect which reduces the biocompatibility of cross-linked tissue. We have attempted to overcome this problem by developing a cross-linking method that obviates incorporation of foreign agents. Our process involves transformation of free carboxyl groups on collagen into acyl azide groups, which react with free amino groups on adjacent side chains. We have shown that the greatest increase in the thermal stability of collagen, as measured by differential scanning calorimetry, is achieved when tissue swelling is inhibited by the addition of sodium chloride (1 M) during acyl azide formation. Under these conditions, the denaturation temperature (Td) of pericardial collagen treated with acyl azide is raised to 83.4 degrees C and that of tissue treated with glutaraldehyde to 85.1 degrees C. Moreover, acyl-azide-treated tissues have the same resistance as glutaraldehyde-treated tissues to chemical solubilization by cyanogen bromide and to enzymatic digestion by collagenase.
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PMID:Use of the acyl azide method for cross-linking collagen-rich tissues such as pericardium. 210 50

The digital flexor tendons of the neonate and adult horse have been compared with respect to variation in extracellular matrix composition along their length. Two pepsin-sensitive, acetic acid soluble proteins, molecular weight (Mr) 52 kD (np 52) and Mr 54 kD (np 54), were prominent throughout the length of neonatal tendons. In adult tendon, np 52 and np 54 were less abundant and restricted to the cannon (metacarpal) region. In contrast, a single pepsin- and collagenase-resistant protein of Mr 55 kD (fp 55) was exclusive to the fetlock (metacarpophalangeal joint) region regardless of age, although more distinct in the adult. Pepsin extracted fp 55 precipitated at 2.0 M sodium chloride: 0.5 M acetic acid and was further purified to homogeneity by bacterial collagenase digestion. Analysis of fp 55 amino acid composition revealed the presence of a large proportion of glycine residues (379 of 1001), suggesting a possible homology with the collagen family. These data demonstrate that the composition of equine digital flexor tendons varies with age, is heterogeneous along its length, and suggests that variation in tendon extracellular matrix composition is influenced by functional requirements.
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PMID:Age- and position-related heterogeneity of equine tendon extracellular matrix composition. 211 5

Single atrioventricular node cells were dispersed by treating the rabbit heart with collagenase. In Tyrode's solution, the cells became rounded, and about 20% of them showed spontaneous activity, whereas the rest remained quiescent. When those quiescent cells were whole-cell clamped, depolarizing clamp pulses from the holding potential of -83 mV induced an outward current which decayed quickly, with a time course similar to that of the transient outward current in the Purkinje fiber. The amplitude of the current became larger when progressively more positive clamp pulses were given from a very negative holding potential. The inactivation time course of this current consisted of two exponential components. Single-channel current recordings from those cells revealed a class of channels that activated more frequently during the initial part of depolarizing pulses. Summation of those unitary currents reproduced activation and inactivation time courses of the macroscopic current well, suggesting that this channel corresponds to the transient outward current. The current-voltage relationship of the channel was linear with the slope conductance of 19.9 +/- 1.8 pS (n = 7), and the reversal potential was near the resting potential of the atrioventricular node cell with 5.4 mM potassium chloride and 134.6 mM sodium chloride in the pipette. The channel was passing mainly potassium ions, but sodium ions also seemed to carry a fraction of the current. The possible role of the transient outward current in the quiescent node cell is discussed.
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PMID:Transient outward current carried by potassium and sodium in quiescent atrioventricular node cells of rabbits. 240 81

Human skin, maintained in serum-free organ culture, secretes a neutral metalloendopeptidase which is remarkably specific for gelatin. Because the product peptides from the action of collagenase on collagen become denatured into random coil polypeptides of 25000 and 75000 daltons at physiological temperature, it is thought that this "gelatinase" is the second, and possibly the only other enzyme in the pathway of extracellular collagen degradation. New types of high-performance liquid chromatography (HPLC) columns have enabled us to improve the yields of active gelatinase from skin culture medium. Raw medium, which has been dialyzed and lyophilized, is fractionated with ammonium sulfate, and applied to Pharmacia Blue Sepharose in a batch step. The 0.4 M sodium chloride eluate is then subjected to gel filtration on Sephacryl S-200, followed by gradient elution from Amicon Green Sepharose. The fractions with gelatinolytic activity are applied to a Bio-Rad TSK-Phenyl-5PW HPLC column for mild hydrophobic chromatography with a gradient of decreasing ammonium sulfate concentration. In the final step, the enzyme is applied to a Pharmacia Mono-Q FPLC column and eluted with a gradient of sodium chloride. At this point, the enzyme appears as two bands, corresponding to enzymatic activity zymograms on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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PMID:Purification of gelatin-specific neutral protease from human skin by conventional and high-performance liquid chromatography. 299 26

Free fat cells and stromal-vascular cells were prepared from rat adipose tissue by incubation with collagenase. NH(4)OH-NH(4)Cl extracts of acetone-ether powders prepared from fat cells contained lipoprotein lipase activity but extracts of stromal-vascular cells did not. Intact fat cells released lipoprotein lipase activity into incubation medium, but intact stromal-vascular cells did not. The lipoprotein lipase activity of the medium was increased when fat cells were incubated with heparin, and this was accompanied by a corresponding decrease in the activity of subsequently prepared fat cell extracts. Heparin did not release lipoprotein lipase activity from stromal-vascular cells. The lipoprotein lipase activity of NH(4)OH-NH(4)Cl extracts of fat cell acetone powders is increased by the presence of heparin during the assay. This increase is not due to preservation of enzyme activity, but to increased binding of lipoprotein lipase to chylomicrons. Protamine sulfate and sodium chloride have little effect on the binding of lipoprotein lipase to chylomicrons, but they inhibit enzyme activity after binding to substrate has occurred. These inhibitors do, however, inhibit the stimulatory effect of heparin on enzyme-substrate binding.
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PMID:The mechanism of heparin stimulation of rat adipocyte lipoprotein lipase. 430 30

A homogeneous population of single cells from the thick ascending limb of Henle's loop (TALH) has been isolated from the rabbit kidney medulla. A total medullary cell suspension was prepared by a series of collagenase, hyaluronidase, and trypsin digestions and separated on a Ficoll gradient (2.6-30.7% wt/wt). Morphologically, the cells isolated from the TALH were homogeneous and showed polarity within their plasma membrane structure, with a few blunt microvilli on their apical surface and deep infoldings of the basal-lateral membrane. Biochemically, the TALH cells were highly enriched in calcitonin-sensitive adenylate cyclase and Na, K-ATPase. Alkaline phosphatase and arginine vasopressin-sensitive adenylate cyclase, highly concentrated in proximal tubule and collecting duct, were present only in low concentrations in the TALH cells. Additionally, furosemide, a diuretic inhibiting sodium chloride transport in the TALH in vivo, inhibited oxygen consumption of the TALH cells in a dose-dependent manner. The TALH cells were viable, as judged by morphological appearance, trypan blue exclusion, the response of oxygen consumption to 2,4-dinitrophenol, succinate and ouabain, and the cellular Na, K and ATP levels.
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PMID:Separation of renal medullary cells: isolation of cells from the thick ascending limb of Henle's loop. 625 27

Volume and morphological changes of the squid giant axons in response to hyper- and hypoosmotic media were examined. In hyperosmotic media, which were made by adding sucrose or sodium chloride to the artificial seawater, the axons behaved approximately as ideal osmometers. The fraction of the osmotically inactive volume was less than 0.05. In hypoosmotic media down to half the osmolality of the artificial seawater, intact squid axons did not show significant volume increases. However, following a combined treatment with hyaluronidase and collagenase, the volume of the squid axons increased in these hypoosmotic media. A wrinkled pattern appeared on the surface of the axons while they were in hyperosmotic media containing excess NaCl or KCl. Trypsin treatment prevented appearance of this surface pattern. Furthermore, no such patterns appeared in media which were made hyperosmotic by the addition of sucrose or sodium glutamate.
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PMID:Osmotic properties of the squid giant axon and their modifications. 631 79


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