Gene/Protein Disease Symptom Drug Enzyme Compound
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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.
Biochem J 1975 Dec
PMID:The substrate specificity of thermomycolase, an extracellular serine proteinase from the thermophilic fungus Malbranchea pulchella var. sulfurea. 0 73

The experiments described in this paper have demonstrated that hepatocytes cultured on floating collagen membranes for periods of 10 days retain their ability to respond to the inducers of drug-metabolizing enzymes, phenobarbital and methylcholanthrene, by increases in cytochromes of the cytochrome P-450 complex. Since the regulation of these cytochromes is the rate-controlling factor in the metabolism of drugs and carcinogens in hepatocytes, such experiments indicate that hepatocytes cultured on floating collagen membranes retain those functions of the liver cell responsible for the metabolism and "activation" of carcinogenic substances. The data support this hypothesis and further indicate that this system may have potential application both in the investigation of hepatocarcinogenesis by chemicals in vitro and as a screening system for the detection of substances truly carcinogenic for the mammalian organism.
Am J Pathol 1976 Dec
PMID:Interaction of chemical carcinogens and drug-metabolizing enzymes in primary cultures of hepatic cells from the rat. 1 97

The endopeptidase, post-proline cleaving enzyme, has been purified 10,500-fold in an overall yield of 18% from lamb kidney. The enzyme possesses a specific activity of 45 mumol/mg/min as tested with the substrate Z-Gly-Pro-Leu-Gly (Km = 6.0 X 10(-5)), has a molecular weight of 115,000, is comprised of two subunits with a molecular weight of 57,000, and exhibits maximal activity at pH 7.5 to 8.0. With the exception of the -Pro-Pro linkage, the -Pro-X-peptide bond (X equals L- and D-amino acid residues) located internally in the peptide sequence can be hydrolyzed (cleavage occurs faster when X = lipophilic side chain as compared to X = acidic side chain). The appropriate -Pro-X- bonds in zinc-free porcine insulin, oxytocin, arginine vasopressin, angiotensin II, bradykinin-potentiating factor were cleaved. Human gastrin, adrenocorticotropic hormone, denatured guinea pig skin collagen, and ascaris cuticle collagen were not degraded. Dipeptides with the structure Z-Pro-LD-X competitively inhibit post-proline cleaving enzyme.
J Biol Chem 1976 Dec 10
PMID:Post-proline cleaving enzyme. Purification of this endopeptidase by affinity chromatography. 1 73

The activity of lysyl oxidase which catalyzes the initial step of cross-linking of collagen and elastin polypeptides was measured in blood vessels of the hypertensive rat. The enzyme activity was increased in the aorta and mesenteric artery when hypertension was induced in 8-week-old rats with administration of deoxycorticosterone acetate (DOCA) and 1% saline. Reserpine diminished this increase in vascular lysyl oxidase activity concomitant with reduction in blood pressure. When beta-aminopropionitrile, a specific inhibitor of lysyl oxidase, was administered before the onset of DOCA-salt hypertension, the aortic collagen content was reduced markedly. Concomitant with reduction in the aortic collagen content, the development of hypertension and arteriosclerotic changes in the kidney was partially prevented. These results would indicate that hypertension increases the amount and the degree of cross-linking of vascular collagen and that the deposition of excess collagen in the vascular wall contributes to the development of hypertension and arteriosclerosis.
Jpn Circ J 1977 Dec
PMID:Increased lysyl oxidase activity in blood vessels of hypertensive rats and effect of beta-aminopropionitrile on arteriosclerosis. 2 27

Scleroderma with its different manifestations is mainly a disease of connective tissue and of vascular system. Next the alteration to collagen, which is demonstrable in lesions by decrease of embryonale collagen type III, there are also humoral and cellular phenomens of autoimmunity. In more than 70% of our patients we found antinuclear antibodies, and in most of them, we found with the leukocytemigration--inhibition-test cellular immunphenomenons to RNA, collagen and muscle. There is a small connection between ageing and immunological defense and repair, accordingly of immunocytes and fibroblasts. Further more precise characterization of this cell-compartments under the aspect of a premature ageing could bring a new understanding in the largely unknown etiopathogenese of scleroderma.
Aktuelle Gerontol 1977 Dec
PMID:[Scleroderma, an ageing process? I. Clinical and immunological aspects (author's transl)]. 2 29

The minimal elasticity of the uterine cervix has been related to its high collagen content. By interfering with cohesive forces that hold the collagen fiber bundle together, it is possible to diminish the physical strength of collagen. Urea has been used in collagen chemistry to dissociate collagen by interfering with hydrophobic linkages and hydrogen bonds. This results in a change of mechanical properties such as a decrease in tensile strength and an increase in elasticity. Basic studies of rat tail tendon demonstrated the additive effects of pH, concentration of urea, and temperature on the mechanical characteristics of collagen fibers. In vitro testing was performed using an injection of 30 per cent urea at pH 4. Serial measurements with a spring gauge instrument showed a reduction in cervical resistance. A cervical injection technique has been developed and toxicity of urea studied.
Am J Obstet Gynecol 1978 Dec 01
PMID:Urea and dilatation of the cervix. 3 Oct 93

To investigate the mechanisms governing collagen interaction with blood platelets, the effects of side-chain modifications on collagen-induced platelet aggregation and release of serotonin were studied. Since many chemical modifications alter the ability of collagen to form fibers that, according to current theory, may complicate interpretation of data, we eliminated this possibility by using collagen stabilized in a native-type fibrillar structure by treatment with either glutaraldehyde or ultraviolet irradiation. Acetylation, methylation, succinylation, treatment with 2,4-dinitrofluorobenzene, 2,4,6-trinitrobenzene sulfonic acid or 1,2-cyclohexanedione, and deguanidination with hypobromite were used to modify collagen side-chain reactive groups: amino, carboxyl, hydroxyl and guanidino. Both unmodified monomeric dispersed and fibrillar collagen preparations initiated platelet aggregation and release, although the kinetics and magnitude of the response were different. Monomeric collagen which had been modified by deguanidination, methylation or succinylation, failed to polymerize in physiological conditions and did not induce platelet aggregation and release. However, none of the chemical modifications of stabilized native-type collagen fibers, except treatment with hypobromite or cyclohexanedione, had an effect on collagen-induced platelet aggregation and release. Both hypobromite and cyclohexanedione modified guanidino groups of arginyl residues. Results showed that the ability of a collagen sample to induce platelet aggregation and release of serotonin is dependent on the arginine content of fibrillar collagen. These data demonstrate that manipulation of amino, carboxyl and hydroxyl groups is unimportant as long as the native-type fibrillar structure is maintained, and that arginyl residues are directly involved in collagen-platelet interaction. Moreover, the data suggest that only the arginyl residues in the Y position of the tripeptide unit Gly-X-Y of collagen are responsible.
Biochim Biophys Acta 1978 Dec 18
PMID:Collagen-induced platelet aggregation and release. I Effects of side-chain modifications and role of arginyl residues. 3 29

The activity of lysyl oxidase (LOX), the extracellular enzyme responsible for initiating crosslinking of collagen and elastin, was measured during 3 types of postnatal lung growth. Lung parenchymal and pleural LOX activity was high in the first 3 wk of of life, decreasing by 50 % to stable amounts by 4 to 10 wk. In contrast, airway and aortic LOX activity remained high during the first 10 wk of life, decreasing by 50 to 75 % thereafter. After pneumonectomy, lung LOX activity doubled within 24 h, decreasing to control values thereafter. Hypoxia (12 to 13 % O2) resulted in a prompt and sustained increase in lung but not pleural, airway, or aortic LOX activity. Thus, LOX activity can be controlled precisely within specific tissues and appears to be related to early phases of connective-tissue synthesis. Further studies of the synthesis and degradation of LOX should provide important information about the control of connective-tissue formation within the lungs.
Am Rev Respir Dis 1979 Dec
PMID:Lung lysyl oxidase activity: relation to lung growth. 4 34

Proteoglycans were identified and localized histochemically and ultrastructurally in normal and hyperplastic arterial intimas in nonhuman primates (Macaca nemestrina). These regions were consistently more alcianophilic than the adjacent medial layers and this alcianophilia was absent after treatment with glycosaminoglycan-degradative enzymes. Ultrastructurally, the intimal intercellular matrix consisted of numerous, irregularly shaped, 200-500-A diameter granules possessing 30--60-A diameter filamentous projections, and these granules were dispersed between collagen and elastic fibers. The granules exhibited a marked affinity for ruthenium red and were interconnected via their filamentous projections. The ruthenium red-positive granules were intimately associated with the plasma membrane of intimal smooth muscle cells and attached to collagen fibrils and elastic fibers. The matrix granules were completely removed after testicular hyaluronidase or chondroitinase ABC digestion but only partially removed after leech hyaluronidase treatment. These results suggest that the matrix granules contain some hyaluronic acid and one or more isomers of chondroitin sulfate. In addition to the large ruthenium red-positive matrix granules, a smaller class of ruthenium red-positive granule (100--200-A diameter) was present within the basement membranes beneath the endothelium and surrounding the smooth muscle cells. Ruthenium red also exhibited an affinity for the surface coat of the smooth muscle cells. The potential importance of proteoglycans in arterial intimal hyperplasia is discussed.
J Cell Biol 1975 Dec
PMID:Proteoglycans in primate arteries. I. Ultrastructural localization and distribution in the intima. 5 34

Rabbit antibodies to bovine basement membrane collagen were used to compare the antigenic determinants of rat parietal yolk sac basement membrane [14C]procollagen with [14C]protocollagen. Basement membrane [14C]protocollagen was found to be less antigenic than basement membrane [14C]procollagen. Hydroxylation of basement membrane [14C]protocollagen, either intracellularly or in vitro with protocollagen prolyl hydroxylase, resulted in restoration of antigenicity. The difference in antigenicity observed between basement membrane [14C]procollagen and basement membrane [14C]protocollagen appeared to depend primarily upon the presence of hydroxyproline in the collagen molecule. Glucosylgalactosylhydroxylysine was found to be unimportant for antigenicity.
J Immunol 1976 Dec
PMID:The role of hydroxylation of proline in the antigenicity of basement membrane collagen. 6 8


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