Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The type IIA rat brain sodium channel is composed of three subunits: a large pore-forming alpha subunit and two smaller auxiliary subunits, beta1 and beta2. The beta subunits are single membrane-spanning glycoproteins with one Ig-like motif in their extracellular domains. The Ig motif of the beta2 subunit has close structural similarity to one of the six Ig motifs in the extracellular domain of the cell adhesion molecule contactin (also called F3 or F11), which binds to the extracellular matrix molecules tenascin-C and tenascin-R. We investigated the binding of the purified sodium channel and the extracellular domain of the beta2 subunit to tenascin-C and tenascin-R in vitro. Incubation of purified sodium channels on microtiter plates coated with tenascin-C revealed saturable and specific binding with an apparent Kd of approximately 15 nM. Glutathione S-transferase-tagged fusion proteins containing various segments of tenascin-C and tenascin-R were purified, digested with thrombin to remove the epitope tag, immobilized on microtiter dishes, and tested for their ability to bind purified sodium channel or the epitope-tagged extracellular domain of beta2 subunits. Both purified sodium channels and the extracellular domain of the beta2 subunit bound specifically to fibronectin type III repeats 1-2, A, B, and 6-8 of tenascin-C and fibronectin type III repeats 1-2 and 6-8 of tenascin-R but not to the epidermal growth factor-like domain or the fibrinogen-like domain of these molecules. The binding of neuronal sodium channels to extracellular matrix molecules such as tenascin-C and tenascin-R may play a crucial role in localizing sodium channels in high density at axon initial segments and nodes of Ranvier or in regulating the activity of immobilized sodium channels in these locations.
 ...
PMID:Interaction of voltage-gated sodium channels with the extracellular matrix molecules tenascin-C and tenascin-R. 986 Oct 42

Viscoelastic property and morphology of fibrin, which is caused by the enzymatic action of thrombin on fibrinogen, was studied quantitatively as a function of antithrombin III (AT) and heparin concentration by adding fibrinogen, heparin, AT, and thrombin, sequentially. A quartz crystal microbalance with impedance analysis (QCM-Z) was used to detect the change of viscoelastic properties as well as the thickness of adsorbed layer during fibrin formation process, while AFM was used to characterize the surface morphology of fibrin layer under the influence of two known anticoagulants. By the addition of fibrinogen initially, a rigid and thin fibrinogen layer with rather smooth surface morphology was formed on the substrate. Then, the addition of thrombin in the absence of AT and heparin, resulted in viscous and thick fibrin gel with textured surface morphology. As an anticoagulant, AT was added before the injection of thrombin, but AT in the absence of heparin showed only marginal effects at higher concentration of AT than that of thrombin. On the contrary, the thick and viscous fibrin layer was altered gradually to more fibrinogen-like layer as the heparin concentration increases at low concentrations of AT, demonstrating the powerful anticoagulant effect by heparin/AT complex. Interestingly, heparin alone without AT was also effective in preventing fibrin formation, influencing the viscoelastic property and morphology of fibrin.
 ...
PMID:Change of viscoelastic property and morphology of fibrin affected by antithrombin III and heparin: QCM-Z and AFM study. 1900 23


<< Previous 1 2