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)

Enzymic hydrolysis, followed by amino acid analysis, provided no evidence for the presence of epsilon-(gamma-glutamyl) lysine or other isopeptide crosslinks in connectin. Gel elecrrophoresis in the presence of sodium dodecyl sulphate did not reveal any difference in connectin between normal and lathyritic muscle, indicating that lysyl oxidase does not initiate cross-link formation in connectin. Although connectin may be covalently crosslinked by some unknown mechanism, the available evidence suggests that the subunit of MW approximately to 900 000 is synthesised as a single polypeptide chain. In developing fetal muscle, myosin heavy chains are apparent some weeks earlier than connectin. This, together with the known susceptibility of connectin to hydrolysis, suggests that connectin exists in an exposed environment rather than as a core to the thick filament.
 ...
PMID:Studies on the structure of connectin in muscle. 717 2

To determine how extracellular matrix and contractile valvular cells contribute to the heterogeneous motion and strain across the mitral valve (MV) during the cardiac cycle, regional MV material properties, matrix composition, matrix turnover, and cell phenotype were related to regional leaflet strain. Radiopaque markers were implanted into 14 sheep to delineate the septal (SEPT), lateral (LAT), and anterior and posterior commissural leaflets (ANT-C, POST-C). Videofluoroscopy imaging was used to calculate radial and circumferential strains. Mechanical properties were assessed using uniaxial tensile testing and micropipette aspiration. Matrix composition and cell phenotypes were immunohistochemically evaluated within each leaflet region [basal leaflet (BL), mid-leaflet (ML), and free edge]. SEPT-BL segments were stiffer and stronger than other valve tissues, while LAT segments demonstrated more extensibility and strain. Collagens I and III in SEPT were greater than in LAT, although LAT showed greater collagen turnover [matrix metalloprotease (MMP)-13, lysyl oxidase] and cell activation [smooth muscle alpha-actin (SMaA), and non-muscle myosin (NMM)]. MMP13, NMM, and SMaA were strongly correlated with each other, as well as with radial and circumferential strains in both SEPT and LAT. SMaA and MMP13 in POST-C ML was greater than ANT-C, corresponding to greater radial strains in POST-C. This work directly relates leaflet strain, material properties, and matrix turnover, and suggests a role for myofibroblasts in the heterogeneity of leaflet composition and strain. New approaches to MV repair techniques and ring design should preserve this normal coupling between leaflet composition and motion.
 ...
PMID:Heterogeneity of Mitral Leaflet Matrix Composition and Turnover Correlates with Regional Leaflet Strain. 2621 89