A-thrombin

Factor V. High in sialic acid content. Factor V is a large asymmetric single-chain glycoprotein that becomes an active participant in the coagulation cascade when it is converted to its active form by a-thrombin. Approximately 25% of human Factor V is found in the whole blood associated with platelets. Factor V is an essential cofactor along with Factor Xa plus phosphohpid plus Ca " in the conversion of prothrombin to thrombin. 

Bode, W., et al. The refined 1.9 A crystal structure of human a-thrombin interaction with D-Phe-Pro-Arg chloromethylketone and significance of the Tyr-Pro-Pro-Trp insertion segment. EMBO ]. 8 3467-3475,... 

As an example of purification via the ELP fusion approach Meyer and Chilkoti (Fig. 9, left), purified the proteins thioredoxin and tendamistat. For this purpose these target proteins and ELP were genetically fused via a short peptide sequence that included a thrombin cleavage site, which allows the removal of the ELP tag after the purification is completed. The general outline of the purification procedure... 

Figure 51-5. Formation of a fibrin clot. A Thrombin-induced cleavage of Arg-Gly bonds of the Aaand B(3 chains of fibrinogen to produce fi-brinopeptides (left-hand side) and the a and p chains of fibrin monomer (right-hand side). B Cross-linking of fibrin molecules by activated factor XIII (factor Xllla).

Alphafoetoprotein, Ancrod, Anti-D Immunoglobulin, Antithrombin III total, Apolipoprotein B, Haemoglobin A2 and F Lysate, Heparin, Protamine Protein C, Fibrinogen, Plasmin a-Thrombin, Antithrombins, (3-Thromboglobulin, Haemiglo-bincyanide... 

G21. DeGroot, P. G Gonsalves, M. D., Loesberg, C., Van Buul-Wortelboer, M. F., Van Aken, W. G and Van Mourik, J. A., Thrombin-induced release of von Willebrand factor from endothelial cells is mediated by phospholipid methylation. J. Biol. Chem. 259, 13329-13333 (1984). 

Kubik M. F Stephens A. W., Schneider D et al. High-affinity RNA ligands to human a thrombin. Nucleic Acids Res 1994 22,2619-26. 

A typical example of such parallelized measurements is given in Figure 20. For a variety of inhibitors, the binding inhibition assay is given for a thrombin inhibition Figure 20 shows the binding curves obtained in parallel from 96 wells37. 

Stimulation by thrombin does not lead to the generation of leukotriene C4 or B4, whereas stimulation of the same mast cells by the calcium ionophore, A23187, does. The secretory response elicited by thrombin is prevented by preincubation with AT-III, a plasma inhibitor of thrombin, or by hirudin, a thrombin inhibitor derived from the leech [135],... 

Figure 12 shows the difference in absorption spectra of the polymer s colorimetric changes upon interaction with the different ions. Note that the absorption wavelength for the polymer/aptamer complex with potassium is distinct from the other ions, all of which have a similar shift. Fluorescence spectra of the polymer/ aptamer transducing complex with the a-thrombin ligand (Fig. 13) indicates a change... 

Fig. 14.11 Selected examples for lead optimization under consideration of multiple parameters simultaneously (A) thrombin inhibitors, (B) p38 MAP kinase inhibitors, (C) MMP-8 inhibitors.

Before beginning therapy, obtain a hematocrit, platelet count, and a thrombin time (TT), activated partial thromboplastin time (aPTT), or prothrombin time (PT)... 

F. Role in therapy Lepirudin is a thrombin-inhibitor indicated for use in the treatment of adults with heparin-induced thrombocytopenia (HIT) type II diagnosis... 

Several electrical aptamer biosensors implemented the biocatalytic hydrolytic activities of thrombin, or the fact that proteins (e.g., thrombin) often include several binding sites for the formation of supramolecular complexes with different aptamers. The bioelectrocatalytic detection of thrombin by an electrical aptasensor was demonstrated by formation of an aptamer-thrombin complex on the electrode, followed by a thrombin-mediated hydrolysis of the nitroaniline-functionalized peptide, (22), yielding the redox-active product nitroaniline, (23), which was analyzed electrochemically76 (Fig. 12.20b). A further bioelectrocatalytic aptasensors configuration is depicted in Fig. 12.20c, where the multidentate formation of aptamer-protein supramolecular complexes was used to analyze thrombin.76 Thrombin includes two different binding sites for aptamers.77 One of the thrombin aptamers... 

Obst U, Gramlich V, Diederich F, Weber L, Banner DW. Design of novel, nonpeptidic thrombin inhibitors and structure of a thrombin-inhibitor complex. Angew Chem Int Ed Engl 1995 34 1739. 

Caflisch A. Computational combinatorial ligand design Application to human a-thrombin. J Computer-Aided Molec Design 1996 10 372-396. 

Shirabe, K., Yubisui, T. Takeshita, M. (1989). Expression of human erythrocyte NADH-cytochrome 65 reductase as a thrombin-cleavable fused protein in Escherichia coli. Biochimica et Biophysica Acta 1008, 189-92. 

The effects of the mutations on functional responses were determined on thrombin receptors that were expressed in Xenopus oocytes. Agonist-stimulated calcium efflux with human a-thrombin (10 nM) and SFLLRNP-NH2 (40 pM), as described previously,29 was employed to determine the functional responsiveness of the receptor. 

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