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)

Lysyl oxidase of bovine aorta was resolved into four enzymically active species by elution from DEAE-cellulose with a salt gradient in 6m-urea, consistent with purification results obtained with enzyme of other tissues [Stassen (1976) Biochim. Biophys. Acta438, 49-60]. In the present study, each of the four peaks of activity was purified to apparent homogeneity by subsequent chromatography on gel-filtration media in 6m-urea. Each enzyme is eluted as a species with mol.wt. approx. 30000 under these conditions, although lysyl oxidase polymerizes to a series of multimers with molecular weights ranging up to 1000000 in the absence of urea. The apparent subunit molecular weight of each enzyme species determined by electrophoresis in sodium dodecyl sulphate and 8m-urea is approx. 32000-33000. The amino acid compositions of the purified forms of lysyl oxidase are similar to each other, although sufficient differences exist to conclude that each is a unique molecular species. Incorporation of alpha-toluenesulphonyl fluoride into the purification scheme does not alter the resolution of enzyme into four species, suggesting that proteolysis during isolation is not the basis of the heterogeneity. The similar sensitivities of each form of enzyme to chelating agents and to semicarbazide and isoniazid indicate that each requires the participation of a metal ion, presumably Cu(2+), and of a carbonyl compound for enzyme function. The present study describes a method for the purification of multiple species of lysyl oxidase and reveals that significant chemical differences exist between the different enzyme forms.
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PMID:Purification and properties of four species of lysyl oxidase from bovine aorta. 3 86

The effects of streptozotocin-induced diabetes and of starvation on the lysyl oxidase activity of rat lung were investigated. Enzyme activity was elevated 2--3 fold in the lungs of streptozotocin-diabetic rats. In contrast, starvation of rats produced a rapid loss of lung lysyl oxidase activity, with levels approximating 25% of control values after 48--72 h of starvation. Enzyme activity was essentially fully restored to control values upon refeeding the 48-h starved animals for 3 h. These studies demonstrate the responsiveness of lysyl oxidase to these physiological states and suggest a component, enzymatic basis of change in lung function known to occur in the diabetic state.
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PMID:Changes in lung lysyl oxidase activity in streptozotocin-diabetes and in starvation. 3 20

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.
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PMID:Lung lysyl oxidase activity: relation to lung growth. 4 34

A model system consisting of highly purified lysyl oxidase and reconstituted lathyritic chick bone collagen fibrils was used to study the effect of collagen cross-linking on collagen degradation by mammalian collagenase. The results indicate that synthesis of approx. 0.1 Schiff-base cross-link per collagen molecule results in a 2--3-fold resistance to human synovial collagenase when compared with un-cross-linked controls or samples incubated in the presence of beta-aminopropionitrile to inhibit cross-linking. These results confirm previous studies utilizing artificially cross-linked collagens, or collagens isolated as insoluble material after cross-linking in vivo, and suggest that increased resistance to collagenase may be one of the earliest effects of cross-linking in vivo. The extent of intermolecular cross-linking among collagen fibrils may provide a mechanism for regulating the rate of collagen catabolism relative to synthesis in normal and pathological conditions.
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PMID:Native cross-links in collagen fibrils induce resistance to human synovial collagenase. 4 86

Lysyl oxidase is the copper-dependent enzyme responsible for the normal cross-linking of both collagen and elastin which is necessary for their functional integrity. There is now strong evidence that this enzyme is vitamin-B6-dependent. The earliest visible lesion of atherosclerosis, commonly found in human neonatal coronary arteries and probably indicative of the location of future atherosclerotic plaques, is a focal splitting of the internal elastic lamina, the cause of which has hitherto remained unexplained. It is suggested that this lesion is the result of imperfect cross-linking of arterial elastin as well as collagen, and is caused by a maternal deficiency of vitamin B6 which is commonly found in pregnancy and which could thus impair the function of lysyl oxidase. Prophylactic supplementation of maternal diet with adequate vitamin B6 is therefore suggested.
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PMID:The aetiological role of maternal vitamin-B6 deficiency in the development of atherosclerosis. 6 31

Considerable difficulty in puriying tissue lysyl oxidase has been previously encountered and the cause of this difficulty has now been ascertained. For these studies, we have used blood plasma lysyl oxidase as a model system. Blood plasma has been shown to contain considerable lysyl oxidase activity. The enzyme exists in a partially or completely inhibited state. Homogeneous preparations of the enzyme from the blood have been obtained by two different methods. Method A yields one form of lysyl oxidase while Method B yields three forms of the enzyme. The methods for the purification of the enzyme and some properties of the enzyme and preliminary data on the lysyl oxidase inhibitor will be discussed.
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PMID:The existence of inhibited lysyl oxidase and the presence of multiple forms. 6 66

It is probable that the conditions obtaining during cellular proliferation occurring as a result of damage to the vessel wall will not be at optimum level. The amino oxidase, lysyl oxidase, is copper-dependent and is required for proper cross-linkage in the maturing fibre. Elastic tissue in blood vessels is normally produced by smooth muscle cells and in circumstances where other cells derived from the blood are involved the production of fibres and ground substance may be altered. Orcein staining alone, or after oxidation with oxone, shows different tinctorial affinities for the fibres in the thickened intima and may indicate some departure from normality in their make-up.
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PMID:Abnormal maturation of elastic fibres in the atherosclerotic intima. 7 96

It has been reported that bovine aorta amine oxidase oxidizes lysine residues in tropoelastin to allysine (Rucker, R.B. and O'Dell, B.L. (1971) Biochim. Biophys. Acta 235, 32-43). Pure bovine aorta amine oxidase was isolate by DEAE-cellulose, hydroxylapatite, Bio-Gel A-1.5 m and concanavalin A-Sepharose 4B chromatography. Enzymatic, chromatographic and immunochemical tests disclosed that pure bovine aorta amine oxidase was not a lysyl oxidase capable of oxidizing the lysine residues of tropoelastin to allysine; The bovine aorta amine oxidase preparation used by Rucker and O'Dell appears to have been contaminated with lysyl oxidase which is the emzyme that oxidizes some of the lysine residues in tropoelastin and tropocollagen to allysine.
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PMID:A purification procedure for the isolation of homogeneous preparations of bovine aorta amine oxidase and a study of its lysyl oxidase activity. 23 99

Two maternal cousins affected by the X-linked form of Ehlers-Danlos syndrome have been observed. Both had congenital heart disease, "floppy valve syndrome", hernias, short stature, stretchable skin and moderate joint hypermobility. Both excreted normal amounts of urinary glycosaminoglycans, almost entirely represented by dermatan sulfate, whose degradation appeared to be inadequate. They also excreted large amounts of hydroxylysine glycosides and L-valyl-proline, considered to be products of degradation of collagen and elastin, respectively. Cultured skin fibroblasts of the propositus synthesized excessively soluble collagen and had a low lysyl oxidase activity. These findings suggest that the increased degradation of structural proteins may be secondary to the defective cross-linking processes caused by the enzymic defect. Addition of (+) catechin, a flavonoid, to the propositus's cultured fibroblasts decreased the abnormal solubility of their collagen.
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PMID:Lysyl oxidase deficiency in Ehlers-Danlos syndrome type V. 24 Jun 45

beta-Aminopropionitrile, a specific inhibitor of lysyl oxidase prevented the rise in blood pressure induced by deoxycorticosterone-salt in rats. In addition, after the onset of hypertension, administration of beta-aminopropionitrile lowered the blood pressure. Concomitant with the lowering of blood pressure, there was a reduction in the more highly crosslinked form of vascular collagen. These findings would indicate that increases in vascular connective tissue are not only sequelae of hypertension, but may also contribute to the maintenance of elevated blood pressure.
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PMID:Reduction of blood pressure and vascular collagen in hypertensive rats by beta-aminopropionitrile. 26 88


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