Factor XIIIa, Human (Fibrinoligase, Plasma Transglutaminase, Fibrin Stabilizing Factor)

Factor XIIIa (FXIIIa) (fibrinoligase, plasma transglutaminase, fibrin stabilizing factor, E.C. 2.3.2.13) is a glutaminyl-peptide g-glutamyl transferase functioning in the final stages of the coagulation cascade, stabilizing the fibrin clot by crosslinking the a- and g-chains of fibrin to form homopolymers (1-4). Several unique features of FXIIIa set it apart from proteins with which it is generally associated. Factor XIIIa is the only non-proteolytic enzyme of the coagulation cascade. Unlike other transamidases, it exists totally in zymogenic form and is the only sulfhydrylase enzyme which functions extracellularly. \n\nPlasma FXIIIa is a tetramer, (Mr=312,000), composed of 2 pairs of non-identical subunits (A2B2) (4-7). Platelet FXIII is a dimer (Mr=46,000), composed of only a pair of identical A subunits (A2) as is factor XIII from all intracellular sources (7-11). The A subunit contains 6 free sulfhydryl groups, one of which is the active center (12). \n\nThe conversion of plasma FXIII (A2B2) to the active transglutaminase, FXIIIa (A2') results from the thrombin catalyzed hydrolysis of the Arg36-Gly37 peptide bond at the NH2-terminal of the A subunit (13). The conformational change induced by this cleavage results in exposure of the active site cysteine. Full activity is achieved only after the Ca2+ dependent (Kd=10e-3M) dissociation of the B subunit dimer from the A2' dimer (14-16). Dissociation of the A2'B2 complex is enhanced by binding to the region of fibrin(ogen) containing residues 242-424 of the Aa chain (14-16). Thus, at normal plasma concentrations of FXIII (90nM), fibrinogen (8uM) and Ca2+ (2.5mM free), all the FXIIIa generated would be in the fully activated (A2') molecular form. Other physiologically relevant crosslinked complexes generated by FXIIIa include fibrin-fibrinogen (17), fibrin-fibronectin (18), fibrin-vWF (19), fibrin-a2antiplasmin (20), fibrin-actin (21), fibrin-thrombospondin, fibronectin-collagen (19), vWF-collagen (19), actin-myosin (21,22), factor V-factor V (23). In addition to clot stabilization, FXIIIa is thought to function in various processes involving cell proliferation, such as wound healing, tissue remodeling, atherosclerosis, and tumor growth.\n\nStabilization of Fibrin: \nThe conversion of soluble fibrin to an insoluble fibrin clot is catalyzed by the transamidase factor XIIIa. Lysine and glutamine side chains of a- and g-chains of fibrin are crosslinked to form homopolymers.\n

Prices direct from United States Biological

Quick response times

Exclusive Biosave savings/discounts

SPECIFICATIONS

Catalog Number

F0019-49A

Size

50ug

Form

Supplied in 50% glycerol, 0.5mM EDTA.

Purity

(same/more than)95% by SDS-PAGE. Plasma Factor XIIIa is generated by cleavage of homogenous plasma Factor XIIIa by alpha-thrombin, in the presence of EDTA. The A2'B2 subunit is purified by ion and affinity chromatography.

References

1. McDonaugh, J., in Hemostasis and Thrombosis, 2nd Edition, eds. R.W. Colman, J. Hirsh, V.J. Marder, E.W. Salzman, pp. 340-357, Philadelphia: J.P. Lippincott Co., 1987. 2. Lorand, L., et al., Methods Enzymol., 80, 333 (1981). 3. Folk, J.E. and Chung, S.I., Methods Enzymol., 113, 364 (1985). 4. Ichinose, A., et al., J. Biochem. Chem., 265, 13411 (1990). 5. Schwartz, M.L., et al., J. Biol. Chem., 248, 1395 (1973). 6. Nagy, J.A., et al., Thromb. Haemostas., 248, 1395 (1973). 7. Hedner, U., et al., Scand. J. Hematol., 14, 114 (1975). 8. Skrynia, C., et al., Blood, 60, 1089 (1982). 9. Chung, S.I., et al., J. Biol. Chem., 249, 940 (1974). 10. Kiesselbach, T.H. and Wagner, R.H., Ann. NY Acad. Sci., 202, 318 (1972). 11. Lopacink, S., et al., Thromb. Res., 8, 453 (1976). 12. Henriksson, P., et al., J. Clin. Invest., 76, 528 (1985). 13. Takagi, T. and Doolittle, R.F., Biochemistry, 13, 750 (1974). 14. Credo, R.B., et al., Biochemistry, 20, 3770 (1981). 15. Credo, R.B., et al., Proc. Natl. Acad. Sci. USA, 75, 4234 (1978). 16. Greenberg, C.S., et al., Blood, 69, 867 (1987). 17. Kamaide, H. and Shainoff, J.R., J. Lab. Med., 85, 574 (1975). 18. Iwanaga, S., et al., Ann. NY Acad. Sci., 312, 56 (1978). 19. Mosher, D.F., et al., J. Clin. Invest., 64, 781 (1979). 20. Sakata, Y. and Aoki, N., J. Clin. Invest., 65, 290 (1980). 21. Mui, P.K. and Ganguly, P., Am. J., Physiol., 233, H346. 22. Cohen, L., et al, Arch. Biochem. Biophys., 192, 100 (1979). 23. Francis, R.T., et al., J. Biol. Chem., 261, 9787 (1986).