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

Lysyl oxidase activity of human normal skins derived from the frontal thighs of 33 subjects showed large variations and the mean value was 11 455 +/- 7 172 (S.D.) cpm/g of wet weight tissue. The age of lesion affected the lysyl oxidase activity in postburn scars. Granulation tissues showed a fairly low activity; however, the activity increased sharply within 2--3 months, and reached a significantly higher value than that of normal skin. The high level of activity continued for up to 2--3 years, then gradually decreased to normal range after 5 years or so. Lysyl oxidase activity was detected only after 4 M urea treatment of tissues. Benzylamine oxidase activity also showed large variations in both normal skins and postburn scars, with mean values of: 0.128 +/- 0.077 (S.D.) and 0.145 +/- 0.090 (S.D.) mmol/g of wet weight/h, respectively. No correlation was observed between lysyl oxidase and benzylamine oxidase activities. The granulation tissues showed significantly high values of benzylamine oxidase activity in contrast to the low values of lysyl oxidase activity.
Clin Chim Acta 1976 Sep 06
PMID:Lysyl oxidase activity in human normal skins and postburn scars. 0 13

Lysyl oxidase is a specific amine oxidase that catalyzes the formation of aldehyde cross-link intermediates in collagen and elastin. In this study, lysyl oxidase from embryonic chick cartilage was purified to constant specific activity and a single protein band on sodium dodecyl sulfate acrylamide gel electrophoresis. This band had an apparent molecular weight of 62,000. The eluted protein cross-reacted with inhibiting antisera developed against highly purified lysyl oxidase. The highly purified enzyme was active with both insoluble elastin and embryonic chick skin or bone collagen precipitated as reconstituted, native fibrils. There was low activity with nonhydroxylated collagen, collagen monomers, or native fibrils isolated from lathyritic calvaria. The maximum number of aldehyde intermediates formed per molecule of collagen that became insoluble was two. These results indicate that lysyl oxidase has maximum activity on ordered aggregates of collagen molecules that may be overlapping associations of only a few collagen molecules across. Formation of aldehyde intermediates and cross-links during fibril formation may facilitate the biosynthesis of stable collagen fibrils and contribute to increased fibril tensile strength in vivo.
J Biol Chem 1976 Sep 25
PMID:Collagen cross-linking. Purification and substrate specificity of lysyl oxidase. 0 1

In this paper, the synthesis of collagen cross-links in vitro was investigated in a defined system consisting of highly purified chick cartilage lysyl oxidase and chick bone collagen fibrils. Cross-link synthesis in vitro was quite similar to the biosynthesis of collagen cross-links in vivo. Enzyme-dependent synthesis of cross-link intermediates and cross-linked collagen derived from lathyritic collagen occurred. The concentration of the two principal reducible cross-links, N6:6'-dehydro-5,5'-dihydroxylysinonorleucine and N6:6'-dehydro-5-hydroxylysinonorleucine, increased to a peak value of approximately two cross-links per molecule and then decreased. Synthesis of histidinohydroxymerodesmosine and a second polyfunctional cross-link of unknown structure began after synthesis of bifunctional cross-links was largely completed and proceeded linearly afterwards. Inhibition of lysyl oxidase after the bulk of bifunctional cross-link synthesis had occurred did not alter the rate of decrease in reducible cross-link concentration but did inhibit further histidinohydroxymerodesmosine synthesis. These results indicate that lysyl oxidase and collagen fibrils are the only macromolecules required for cross-link biosynthesis in vivo. It is likely that the decrease in reducible cross-links observed during fibril maturation results from spontaneous reactions within the collagen fibril rather than additional enzymatic reactions.
J Biol Chem 1976 Sep 25
PMID:Collagen cross-linking. Synthesis of collagen cross-links in vitro with highly purified lysyl oxidase. 0 2

A total of 160 1-2 day old chickens were fed a 2% cholesterol diet for a period of 8 to 42 days and compared with an equal number of controls. Aortas were analyzed for various indexes of reactivity of connective tissue, cholesterol content and scanning electron microscopy (SEM) characteristics of the endothelial lining. Cholesterol feeding for a period up to 6 weeks resulted in doubling the level of serum cholesterol. It was, however, without effect on the activity of prolyl hydroxylase, lysyl oxidase, collagenase and collagen content in the aortic wall. As early as 3 weeks of feeding significant changes occurred in total and esterified cholesterol content. At the same time endothelial cells were characteristically contracted with several long cytoplasmic elongations and protrusions. A significant decrease of activity of the above enzymes was found in aortic tissue with increased age of the chicken. Collagen content in aortas increased with age of chickens. It is concluded that cholesterol as an atherogenic agent induces marked changes in endothelial cells and lipids of chicken aorta at earlier periods, prior to the activation of connective tissue.
Atherosclerosis 1976 Sep
PMID:Early changes in the arterial wall of chickens fed a cholesterol diet. 0 48

The formation of isodesmosine and desmosine in vitro by the action of lysyl oxidase on tropoelastin was studied. The synthesis of desmosines occurred in the absence of additional substances. The formation of desmosines was not affected by removal of molecular O2 from the reaction medium nor was it affected by the lack of proline hydroxylation in tropoelastin. However, there was virtually no desmosine formation at 15 degrees C, a temperature not conducive to coacervation, indicating that coacervation is an important prerequisite for cross-linking.
Biochem J 1978 Sep 01
PMID:Elastin cross-linking in vitro. Studies on factors influencing the formation of desmosines by lysyl oxidase action on tropoelastin. 3 Apr 49

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.
Biochem J 1979 Sep 01
PMID:Native cross-links in collagen fibrils induce resistance to human synovial collagenase. 4 86

Evidence is presented that indicates tropoelastin is derived from a soluble elastin with a molecular weight of 95000. Tropoelastin and its proposed precursor were isolated from the aortas of copper-deficient chicks. Although it is doubtful that the proposed precursor is an initial product of elastin translation, i.e., a proelastin, it is proposed to be at least a truncated form of proelastin that is converted to tropoelastin. The key to its isolation was the presence of alpha 1-antitrypsin at each step in the purification procedure. The first 11 amino acid residues at the NH2 terminal of the proposed tropoelastin precursor (GGVPGVAVPGGV) are the same as those for tropoelastin. Its amino acid composition is similar to that of tropoelastin, except for higher amounts of acidic amino acid residues. Further, the proposed precursor contains a limited number of aldehydic functions, presumably in the form of peptidyl allysine. This was taken as an indication that the proposed precursor serves as a substract for lysyl oxidase. Under the conditions used for the isolation, the precursor appeared to be in higher concentrations than tropoelastin in aorta extracts from copper-deficient chicks.
Biochemistry 1979 Sep 04
PMID:Partial characterization of a tropoelastin precursor isolated from chick aorta. 48

Connective tissues such as blood vessels are known to be greatly affected by age because of impaired functional properties and increased susceptibility to diseases. With the aim of providing further information on the role of the extracellular matrix in age-related modifications, we investigated the aorta in the rat model from birth to senescence by means of morphological and morphometric observations and by evaluation of lysyl oxidase activity. Results focused on the dramatic vascular rearrangements due to progressive fibrosis of the extracellular matrix and on prominent elastin modifications. The presence of lysyl oxidase activity, even in the oldest animals, might be at least partly responsible for the increased stiffness of the aging extracellular matrix. The striking age-related remodeling of the aortic architecture and the alterations of the interactions between cellular and extracellular compartments might greatly influence the functional properties of the arterial wall in senescence, at least contributing to the consequences of some apparently age-related vascular disorders.
Arterioscler Thromb 1992 Sep
PMID:Role of the extracellular matrix in age-related modifications of the rat aorta. Ultrastructural, morphometric, and enzymatic evaluations. 135 19

When beta-aminopropionitrile (BAPN) is added to neonatal rat aortic smooth muscle cell cultures there is a decrease in insoluble elastin accumulation with a concomitant increase in tropoelastin and tropoelastin fragments in the culture medium. The experiments described here examine the biological significance of this fragmentation. BAPN, as well as purified tropoelastin fragments isolated from spent medium of cells grown in the presence of BAPN, were added to cultures. A decrease in elastin mRNA was observed in cultures grown in the presence of BAPN and also in those cultures to which the purified tropoelastin moieties were added. These studies indicate that the inhibition of lysyl oxidase by BAPN prevents elastin crosslinking which results in an increase in tropoelastin moieties, thus leading to a down regulation of the steady state levels of elastin mRNA.
Biochem Biophys Res Commun 1991 Sep 16
PMID:The effect of beta-aminopropionitrile on elastin gene expression in smooth muscle cell cultures. 168 Mar 24

Lysyl oxidase catalyzes the oxidation of peptidyl lysine to alpha-aminoadipic-delta-semialdehyde, the precursor to the covalent crosslinkages that stabilize fibers of elastin and collagen. This enzyme contains both copper and a carbonyl cofactor consistent with an o-quinone. The proposed mechanism of action is derived from available kinetic and chemical data and also can account for mechanism-based inhibition of the enzyme by specific monoamines and diamines. Recent evidence for biosynthetic precursors and for the regulation of lysyl oxidase in fibrotic and malignant diseases is discussed.
Am J Respir Cell Mol Biol 1991 Sep
PMID:Properties and function of lysyl oxidase. 191 Aug 5


1 2 3 4 5 6 7 8 9 10 Next >>