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Query: HUMANGGP:031673 (collagen)
 124,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specificity of thermomycolase toward glucagon and the oxidized A and B chains of insulin was investigated. Extensive digestion of glucagon occurred when conducted at pH 7.0 and 45 degrees C for 40 min, whereas hydrolysis of only three peptide bonds occurred at pH 7.0 and 28 degrees C for 5 min. A similar situation was observed for the oxidized B chain of insulin, which exhibited only a single major cleavage after 5 min at 25 degrees C. No well-defined specificity for particular amino acid residues was evident, but ready hydrolysis of peptide bonds occurred within sequences containing non-polar residues. This endoproteinase must therefore possess an extended hydrophobic binding site for polypeptides. Thermomycolase hydrolysed acetylalanylalanylalanine methyl ester and elastin-Congo Red at 22 and 8.5 times the rate of porcine elastase respectively. A limited degradation of native collagen and significant hydrolysis of benzyloxycarbonyl-Gly-Pro-Leu-Gly-Pro were suggestive of some collagenase-like activity. No keratinase activity was apparent.
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PMID:The substrate specificity of thermomycolase, an extracellular serine proteinase from the thermophilic fungus Malbranchea pulchella var. sulfurea. 0 73

The optimum conditions for the selective removal of elastin from connective tissues are described. The process, elastolysis, consists of incubating small samples of connective tissue in buffered saline at ph=8.6 containing 300 microgram/me of a 50-50% mixture of elastase with trypsin inhibitor, for 5-6 hours at room temperature. This process, complimented with other processes for selective removal of lipids, or mucopolysaccharides, or collagen, enables one to examine the contribution of the various components of the connective tissue to its mechanical function. The elastolysis was tested with aortic, valvular and tendon tissues from human, bovine and canine species and it was found that in tensile stress experiments, collagen was unaffected while the low-stress contribution of elastin disappeared.
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PMID:Use of enzymolysis techniques in studying the mechanical properties of connective tissue components. 2 17

Experimental lathyrism was produced in young albino mice with a diet containing 50% sweet pea seed (Lathyrus odoratus). After 7 days on the lathyritic diet, sections of themandibular molar and incisor periodontal ligaments, when oxidized and treated with aldehyde fuchsin, demonstrated enhanced staining of the oxytalan fibers and numerous vessels. At this time aldehyde fuchsin or orcein also revealed marked pathological changes in the periodntal ligament of all molars. When athyrism was prolonged for 12 weeks, both the molar and incisor oxytalan systems were still readily identifiable although the molar periodontal ligament continued to be serverely affected by lathyrism. The oxytalan fibers retained their characteristic tooth-vascular association in all of the lathyritic mice. Oxytalan fibers of the lathyritic and control animals showed similar reactions to enzyme digestion with beta-glucuronidase, elastase, and pepsin. However, gingival elastic fibers reacted in a different way from oxytalan fibers with beta-glucuronidase and elastase treatment. These findings indicate that in the lathyritic mouse the oxytalan fiber system of functioning teeth possesses a high degree of permanence and is metabolically distinct from collagen and elastic fibers.
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PMID:The oxytalan fiber system in the mandibular periodontal ligament of the lathyritic mouse. 6 1

A number of soluble proteins contained in human aortic intimal tissue was extracted into buffered saline (pH 7.4) and identified and quantitated by immunoelectrophoresis and immunodiffusion. The proteins included IgA, IgG, IgM, B1C (C3), alpha 1-antitrypsin, alpha 2-macroglobulin, fibrinogen, albumin, LDL, HDL, alpha 1-acid glycoprotein, beta 2-glycoprotein, transferrin and ceruloplasmin. The concentration of soluble proteins was significantly higher in the atherosclerotic intima than in the normal intima. The diseased intima also contained a small amount of tissue-bound IgG, IgA and B1C which was extractable with citrate buffer at pH 3.2. The vascular band IgG, and B1C were shown by enzymatic and immunohistochemical studies to be closely associated with the collagenous tissue of the plaque. The Ig contained in the atherosclerotic plaque may be derived in part from the biosynthesis of Ig by the artery, since the incorporation of 14C-labeled leucine into IgG by the atheromatous plaque was demonstrable by radioimmunoelectrophoresis. In contrast to the diseased artery, the normal artery did not synthesize IgG and did not contain vascular bound IgG or complement. However, the normal artery was capable of fixing IgG and B1C eluted from the diseased artery. The present studies suggested that the IgG contained and synthesized by the plaque might represent an immune response to an endogenous or exogenous antigen closely associated with plaque collagen. IgG and B1C either alone or in the form of an immune complex also may play an important role in phagocytosis in the plaque and thereby influence the course of atherosclerosis. The proteolytic inhibitors, alpha 1-antitrypsin and alpha 2-macroglobulin, found in relatively high concentrations in the plaque, could enhance fibrosis of the lesion because of thier known inhibitory effects on collagenase and elastase.
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PMID:Soluble proteins in the human atherosclerotic plaque. With spectral reference to immunoglobulins, C3-complement component, alpha 1-antitrypsin and alpha 2-macroglobulin. 9 93

The production of proteases was investigated during growth of dermatophytic fungi with special emphasis on Trichophyton rubrum. Exogenous glucose suppressed elastase production in all dermatophytes examined. The production of protease active guinea pig hair in keratin-salts broth by Microsporum gypseum. Trichophyton mentagrophytes and T. rubrum was also suppressed by glucose. Various carbohydrates added to keratin-salts broth curtailed protease production by T. rubrum as did individual amino acids but ammonium phosphate did not. Enzyme activities against guinea pig hair were compared in twenty-one diverse clinical isolates of T. rubrum cultured in keratin-salts broth. Activity also occurred towards casein, bovine serum albumin, keratin, collagen and elastin after keratin-growth. Studies concerning the properties of enzyme activities in culture filtrates of T. rubrum after keratin-growth suggested that multiple proteases occurred here. Hydrolysis of guinea pig hair and elastin were optimal at pH7 while keratinase was most active at alkaline pH. Divalent cations stimulated protease(s). Ferric ion and mercuric ion stimulated keratinase but were inhibitory to guinea pig hair hydrolysis and elastase. Chelating agents inhibited elastase and the hydrolysis of guinea pig hair more severely than keratinase and all of those effects were reversed by excess calcium. A serine-protease inhibitor, phenylmethylsulfonylfluoride (PMSF), curtailed keratinase but was less inhibitory to elastase and guinea pig hair hydrolysis. Soybean trypsin inhibitor arrested each protease.
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PMID:Control of exocellular proteases in dermatophytes and especially Trichophyton rubrum. 9 67

1. The contents of the fibrous proteins collagen and elastin in the pleural and parenchymal regions of bovine lungs were determined. The collagen content was approx. 70% (g/100g of salt-extracted defatted powder) in each tissue, and the elastin content was 28% in pleura and 13.5% in parenchyma. 2. Purification of the insoluble collagen from the pleura and parenchyma of bovine lungs by various methods was attempted. The collagen fractions isolated after incubation of the pulmonary tissues with the proteolytic enzymes collagenase ("collagenase-soluble" fraction) or pancreatic elastase ("elastase-insoluble" fraction) each contained approx. 87% of the total collagen initially present. 3. Both collagen fractions were chemically analysed for their amino acid and carbohydrate contents and were found to be similar to those of the intact interstitial collagens isolated from skin, bone and tendon. 4. The contents of the two aldimine cross-linking compounds, dehydrohydroxylysinonorleucine and dehydrodihydroxylysinonorleucine, were determined in the bovine pulmonary collagen fractions, and were found to decrease with increasing age of the animals, and were similar to the values found in intact collagens from bone and tendon.
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PMID:Isolation and chemical characterization of collagen in bovine pulmonary tissues. 16 65

Both clinical and experimental evidence implicate proteolytic enzymes active against elastin in the pathogenesis of emphysema. Paradoxically, however, the elastin content of emphysematous human lungs at autopsy has been normal. When emphysema was produced in hamsters by a single intratracheal injection of 25 units of porcine pancreatic elastase, the elastin content of the lungs was reduced from 1.40 +/- 0.22 mg. in controls to 0.43 +/- 0.10 mg. 24 hours after injection, and histologic sections showed that many elastic fibers had disappeared. The elastin content of the lungs gradually increased, approaching normal values by 2 months after injection. The incorporation of 14C-proline into elastin was markedly elevated during the first 2 weeks after injection, decreasing nearly to normal by 2 months. The synthesis of collagen was also increased, indicated by an increase in the collagen content of the lung, an increase in the prolyl hydroxylase activity, and an increase in incorporation of labeled proline into collagen. During the period of active resynthesis of elastin, small clumps of microfibrils and elastic fibrils were visible by electron microscopy within grooves on the surface of septal connective tissue cells in the lungs. Many elastic fibers seen in histologic sections up to 4 months after injection were of abnormal configuration and disorganized.
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PMID:The induction of emphysema with elastase. II. Changes in connective tissue. 17 9

A previous study of hamsters, 21 days after intratracheal treatment with pancreatic elastase, showed development of emphysema, shift of the volume-pressure curve up an to the left, with both air and saline filling, and increase in quasistatic lung compliance. There was also a striking increase in vital capacity and lung volume at transpulmonary pressure of 25 cm H2O (TLC25); however, 21 days after collagenase treatment, there was only a slight increase in TLC25. The lung volume changes were not consistent with the theory that the collagen fiber network is responsible for limiting distension of the lung. This report considers saline-filled volume-pressure curves studied in excised hamster lungs after incubation with endotracheally instilled pancreatic elastase or clostridial collagenase solutions. Fluid retained in the lungs after the first infusion-withdrawal cycle was significantly greater in lungs treated with elastase than in lungs treated with collagenase or in control lungs. Total fluid volume at full inflation was similar in the 3 groups. Chord compliance of lungs treated with collagenase was greater at high volume range than that in lungs treated with elastase or control lungs; chord compliance of elastase-treated lungs was higher at mid-volume range than that of collagenase-treated or control lungs. The results of these in vitro studies are consistent with the theory of independently functioning elastic and collagen fiber networks, with the latter limiting lung distensibility at high volumes, and the former providing great extensibility at low volumes. Events that are part of the repair process after elastase injury may result in a change in the orientation of collagen in alveolar tissue and appear to account for the differing effects of in vivo and in vitro elastase treatment on the static mechanical properties of the lungs.
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PMID:In vitro effects of elastase and collagenase on mechanical properties of hamster lungs. 18 Aug 55

The alteration of the structural organization of dermal connective tissue was studied by light and electron microscopy and by biochemical techniques in normal human and in diabetic patients using skin biopsies. Part of the tissue was used for light and electron microscopy, the rest was incubated in the presence of 3H-lysine for four hours. The 3H-lysine labelled biopsies were submitted to a sequential extraction procedure in order to obtain representative macromolecular fractions containing the matrix macromolecules. The extracts were analyzed for their chemical composition and radioactivity. Electron microscopy revealed ultrastructural modifications of the fibroblasts, of the collagen and elastic fibers in the diabetic dermis. Fibroblasts contained an increased amount of electron dense deposits in the cytoplasm and dilated endoplasmic reticulum. The collagen bundles were dissociated. Elastic fibers under the epithelial basal laminae were fragmented or absent. The incorporation pattern of 3H-lysine into these macromolecular fractions was different in the normal and diabetic skin biopsies. The percentage of total radioactivity incorporated increased significantly in the 1M CaCl2 extractable fraction an in the 6M urea extractable fraction and decreased significantly in the collagenase and elastase extracts in diabetic skin biopsy. These results demonstrate the existence of morphological and biochemical alterations in diabetic connective tissue (dermis) reflecting alterations in the relative rates of synthesis and/or degradation of the intercellular matrix macromolecules as well as of their microarchitectural arrangement.
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PMID:[Structural and biochemical alterations of human diabetic dermis studied by H-lysine incorporation and microscopy]. 18 19

Traditionally, ligaments and tendons (L and T) have been regarded as metabolically inert structures. However, sufficient biochemical evidence on the metabolism of collagen has indicated that such a concept is no longer tenable. To determine whether L and T respond to increased or decreased levels of chronic exercise, studies were undertaken to measure their aerobic capacities. For comparative purposes, similar measurements were obtained from liver and skeletal muscles secured from normal and hypophysectomized male rats. Oxygen consumption and cytochrome oxidase (CO) activity was recorded from cell suspensions that had been prepared with the inclusion of collagenase and with elastase added to the medium. The O2 results showed that L and T had values that were approximately 10 times lower than liver tissue and 7.5 times less than the means from skeletal muscles. Hypophysectomy caused marked reductions in O2 uptake of liver and muscle tissues; but had no impact on L and T. When CO activity of these connective tissues were evaluated, immobilization and hypophysectomy caused significant reductions that ranged from -36% to -59% respectively. Training, on the other hand, resulted in increases of less than 10% in the activity of this enzyme within L and T while being elevated in muscle tissue by 58%. It was concluded that the metabolic activity of L and T was lowered with decreased levels of physical activity but it was unclear why chronic exercise did not produce the opposite effect.
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PMID:Physical activity and hypophysectomy on the aerobic capacity of ligaments and tendons. 20 28


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