Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.3.13 (lysyl oxidase)
 1,248 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study assessed the responses of lysyl oxidase, the enzyme that initiates covalent crosslinking in elastic and collagen, by studying the aortic tissue of rabbits after arteriosclerosis had been induced by diet. Rabbits in the experimental group were fed an atherogenic diet of rabbit chow supplemented with 8% peanut oil and 2% cholesterol for varying periods of time, while the control group was fed only rabbit chow. Lysyl oxidase activity was found to be distributed throughout the length of the thoracic and abdominal aortas of the normal rabbits, However, rabbits fed the atherogenic diet showed marked increases in enzyme in the aortic arch, a change that was initially evident after 30 days and became greatest (2.5 times that of the controls) after 90 days. Enzyme activity in the study rabbits increased only minimally in the abdominal aortic wall. Aortic prolyl hydroxylase activity measured after 60 days of feeding changed in degree and manner similar to lysyl oxidase activity. These region-specific changes in enzyme activities correlated with the distribution and severity of aortic lesions in this model of the disease. Lysyl oxidase activity increased dramatically in this model of atherosclerosis, suggesting that this extracellular enzyme activity may prove to be a vulnerable and accessible point of control of the fibrotic response in atherosclerosis.
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PMID:Changes in aortic lysyl oxidase activity in diet-induced atherosclerosis in the rabbit. 611 70

Industrial workers who are accidentally exposed to cadmium fumes often develop severe lung damage leading to widespread peribronchiolar scarring. This study examined the effect of a single exposure of cadmium chloride aerosol on rat lung lysyl oxidase and prolyl hydroxylase, both markers of connective tissue biosynthesis. Rats were killed at 2, 4, 7, 10, and 21 days after a 2-h exposure to 0.1% Cdcl2 aerosol. Total lung lysyl oxidase was increased 14.8 times that a saline control animals by 4 days and returned to near normal values by 10 days. Interestingly, a small amount of lysyl oxidase activity was also detectable in the lung lavage of unexposed animals and was markedly elevated at the earlier times after cadmium exposure. Total lung prolyl hydroxylase activity paralleled that of lung lysyl oxidase and increased 7.4-fold by the fourth day. A significant increase in total lung hydroxyproline could be demonstrated. Administration of beta-aminopropionitrile, an irreversible inhibitor of lysyl oxidase, prevented much of the increase in lysyl oxidase activity and the accumulation of collagen. The altered tissue amounts of lysyl oxidase and prolyl hydroxylase after cadmium inhalation correlated well with the marked interstitial cell hyperplasia 4 to 5 days after exposure and suggested that connective tissue protein synthesis is activated in the interstitial cell fibroblasts soon after cadmium exposure.
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PMID:Lung lysyl oxidase and prolyl hydroxylase: increases induced by cadmium chloride inhalation and the effect of beta-aminopropionitrile in rats. 611 50

Lysyl oxidase and collagenase activities were measured in experimental acute and chronic liver injury in mice and rats, and correlated with collagen synthesis and accumulation. Acute liver injury was induced in mice and rats by a single dose of carbon tetrachloride given by gavage, and also in mice by a single injection of murine hepatitis virus. Chronic liver injury was induced in rats by repeated injections of carbon tetrachloride. Elevated plasma glutamic oxaloacetic transaminase levels, increased hepatic prolyl hydroxylase activity, and increased synthesis of collagen-bound hepatic hydroxyproline occurred in animals with acute as well as with chronic liver injury. However, only chronic liver injury appeared to be associated with fibrosis, increased collagen-bound hydroxyproline content, increased hepatic lysyl oxidase and collagenase activities, as well as with increased serum lysyl oxidase activity. These data suggest that lysyl oxidase and collagenase may play an important role in the collagen accumulation associated with hepatic fibrosis.
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PMID:Lysyl oxidase and collagenase in experimental acute and chronic liver injury. 611 72

Biochemical and mechanical experiments were conducted to determine the effect of dietary thiamine on collagen maturation during wound repair. The breaking strength of excised wounds, the isometric shrink tension of skin, and the lysyl oxidase activity of normal and repairing skin were determined. Rats were divided into three dietary groups and fed either a thiamine-deficient diet (-B1), a thiamine-deficient diet supplemented with 1 mg thiamine-HCl (+B1) or a thiamine-deficient diet supplemented with 3 mg thiamine-HCl (+3B1). When -B1 rats were demonstrated to be deficient in urinary thiamine, all animals were wounded. Ten days after wounding the animals were killed and the tissues harvested. Significant differences were observed in lysyl oxidase activity between -B1 and +B1 in both wounded and unwounded tissue, and in isometric shrink tension between -B1, +B1, and breaking strength between all three dietary treatment groups. The changes observed in this study demonstrate a definite involvement of thiamine in wound repair and scar development.
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PMID:Effect of dietary thiamine on intermolecular collagen cross-linking during wound repair: a mechanical and biochemical assessment. 612 Feb 45

Biochemical abnormalities were studied in two brothers with bladder divericulas, inguinal hernias, slight skin laxity, and hyperelasticity and skeletal abnormalities including occipital exostoses. Lysyl oxidase activity was low in the medium of cultured skin fibroblasts, this abnormality being accompanied by reduced conversion of the newly synthesized collagen into the soluble form. Copper concentrations were markedly elevated in the cultured skin fibroblasts, but decreased in the serum and hair. Serum cerulophasmin levels were also low. The reduced lysyl oxidase activity is suggested to be responsible for ther clinical manifestations, but the deficiency in this copper-dependent enzyme may be secondary to the abnormalities in the metabolism of the cation. Nevertheless, a mutation directly affecting both lysyl oxidase and an intracellular copper transport protein cannot be excluded. The disease is tentatively classified as one subtype of the Ehlers-Danlos syndrome.
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PMID:Abnormal copper metabolism and deficient lysyl oxidase activity in a heritable connective tissue disorder. 612 Sep 54

Hepatic collagen synthesis was studied during progressive fibrosis induced by carbon tetrachloride in male Sprague-Dawley rats by determination of lysyl oxidase activity, hydroxyproline levels and morphological assessment. The activity of lysyl oxidase was increased significantly when fibrosis became apparent histologically.
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PMID:The activity of lysyl oxidase in experimental hepatic fibrosis. 612 94

A mild form of emphysema was produced in pigs raised on a copper-deficient, zinc-supplemented diet. The copper-requiring enzyme, lysyl oxidase, catalyzes the cross-linking of tropoelastin into mature elastin. Zinc further inhibits the activity of lysyl oxidase. Lungs from animals raised on copper-deficient, zinc-supplemented diets of demonstrate perforations in alveolar walls and diminished amounts of elastin bronchi and pulmonary arteries. Mean linear intercepts are greater and alveolar internal surface areas are less than those in control animals, fulfilling the generally accepted definition of emphysema. Physiologic confirmation is provided by a leftward shift of the saline volume-pressure curves when compared with those in control animals. Ultrastructurally, the alveolar walls are effaced and pores of Kohn are enlarged. There are areas in which elastin is absent leaving remnant microfibrils, and there are other changes consistent with active elastin synthesis. Biochemical data demonstrate no difference in elastin content as micrograms/ml of fat-free dry weight but do demonstrate increased collagen content in experimental animal lungs compared with that in control lungs. Ultrastructural similarities to enzyme-induced models of emphysema suggest the presence of elastin degradation in our model. We speculate that although the copper-deficient, zinc-supplemented state may stimulate protein synthesis in general, elastin is being degraded by endogenous means, but collagen is not.
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PMID:A copper-deficient, zinc-supplemented diet produces emphysema in pigs. 612 18

The synthesis of collagen (measured as the formation of non-dialyzable hydroxyproline) and other proteins, and the activity of lysyl oxidase, the enzyme responsible for the formation of cross-links in elastin and collagen, were measured in cultured human aortic smooth muscle cells in the presence of various cortisol concentrations. In addition, the effect of cortisol on the proliferation of the cells was also studied. At concentrations of 10(-6) M and greater, cortisol retarded cell growth markedly, as judged by decreased incorporation of 3H-thymidine by the cells and decreased DNA content of the cultures. At the same concentrations, cortisol increased the synthesis of collagen and other proteins. The magnitude of the increase was similar for collagen and other proteins. The activity of lysyl oxidase was also increased in the presence of 10(-6) and 10(-5) M cortisol, but to a lesser extent than the synthesis of collagen. Other studies using cultured cells have shown that cortisol decreases the synthesis of hyaluronic acid but not of sulphated glycosaminoglycans by smooth muscle cells and does not injure endothelial cells. Considering these findings in the light of the present results, it is suggested that cortisol induces changes in the metabolism of connective tissue macromolecules of smooth muscle cells that can be regarded as atherogenic. However, some other important biological changes associated with atherogenesis (smooth muscle cell proliferation and endothelial injury) do not occur in vascular cells exposed to cortisol.
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PMID:Effect of cortisol on the proliferation and protein synthesis of human aortic smooth muscle cells in culture. 612 4

The palmar aponeurosis removed from ten patients with Dupuytren's contracture was studied using morphological and biochemical approaches. The histological characteristic of Dupuytren's contracture is the presence of numerous nodules among the lamellar structures of the collagen fibres. In the nodules, there are many active fibroblasts which are surrounded by immature fibres and metachromatic substances demonstrated by toluidine blue staining. Ultrastructurally, the active fibroblasts have the characteristics of myofibroblasts, as previously reported by Dr. Gabbiani. We found that some fibroblasts have intracellular collagen fibrils in the cytoplasm. When assayed by Siegel and Martin's method, lysyl oxidase activity of the palmar aponeurosis was significantly higher in Dupuytren's contracture than in normal hands. Biochemical studies such as electrophoretic analysis of mucopolysaccharides, determination of uronic acid and collagen contents were undertaken to compare the aponeurosis of Dupuytren's contracture with normal cases. The uronic acid contents were higher in Dupuytren's contracture than in the controls. However, no difference between the two groups was found in the collagen contents and in the composition of the mucopolysaccharides. These characteristic features; existence of myofibroblasts and intracellular collagen fibrils and increase in the activity of lysyl oxidase probably play a significant role in the establishment of flexion contracture of the fingers in Dupuytren's contracture.
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PMID:Dupuytren's contracture: morphological and biochemical changes in palmar aponeurosis. 613 30

Lysyl oxidase purified from bovine aorta can oxidize simple alkyl mono- and diamine substrates yielding the respective aldehyde, H2O2, and ammonia as products. The oxidation of such substrates is limited to approximately 100 catalytic turnovers per enzyme molecule since lysyl oxidase is syncatalytically and irreversibly inactivated in the course of oxidation of these amines. The present study reveals that addition of oxidant scavengers protects significantly against inactivation of lysyl oxidase and that the ammonia product is a reversible competitive inhibitor of amine oxidation. Further, the enzyme becomes covalently labeled by the amine substrate or its enzyme-processed derivative during catalysis. Thus, lysyl oxidase appears subject to multiple modes of catalysis-dependent inhibition or inactivation. Syncatalytic inactivation of lysyl oxidase might represent a means of restricting the activity of this enzyme toward its elastin and collagen substrates in vivo.
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PMID:Multiple modes of catalysis-dependent inhibition and inactivation of aortic lysyl oxidase. 613 46


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