Factor X, Human

Human Factor X is a vitamin K-dependent protein zymogen which is synthesized in the liver and circulates in plasma as a two chain molecule linked by a disulfide bond (1,2). Prior to secretion into plasma, post-translational modifications produce 11 gamma-carboxyglutamic acid (gla) residues and a single b-hydroxyaspartic acid residue, which are located within the NH2-terminal light chain. The light chain also contains two epidermal growth factor (EGF) homology domains. The COOH-terminal heavy chain of factor X contains most of the carbohydrate moieties, as well as the latent serine protease domain. The activation of factor X is catalyzed by either the intrinsic factor X-ase complex (factor IXa, factor VIIIa, cellular surface and calcium ions) or the extrinsic factor X-ase complex (factor VIIa, tissue factor, cellular surface and calcium ions). \n\nActivation of human factor X by either complex results in cleavage at Arg52-Ile53 of the COOH-terminal heavy chain and subsequent release of a 52 amino acid activation glycopeptide. Factor Xa then serves as the enzyme component of the prothrombinase complex which is responsible for the rapid conversion of prothrombin to thrombin. The gla residues enable factor X/Xa to bind phospholipid (i.e. cell surfaces) in a calcium dependent manner; a requirement for assembly of the prothrombinase complex. \n\nThe first EGF homology domain contains a Ca+2 binding site which acts as a hinge to fold the EGF and GLA domains towards each other (12). This region of the molecule is involved in the recognition of cellular binding domains.\n\nStructure:\nTwo subunits, Mr=16,200 and 42,000, NH2-terminal gla domain, and two EGF domains.\n\nIsoelectric point:\n4.9

Prices direct from United States Biological

Quick response times

Exclusive Biosave savings/discounts

SPECIFICATIONS

Catalog Number

F0018-01

Size

100ug

Form

Supplied as a liquid in 50% glycerol/H2O.

Purity

(same/more than)95%. Human factor X is isolated from fresh frozen human plasma by a combination of conventional techniques and immunoaffinity chromatography. Purity is determined by SDS-PAGE analysis and activity is measured using a factor X clotting assay.

References

1. Davie, E.W., et al., Adv. Enzymol. 48: 277 (1979). 2. Jackson, C.M., Ann. Rev. Biochem. 49: 765 (1980). 3. Bajaj, S.P., et al., Prep. Biochem. 11: 397 (1981). 4. Church, W.R., et al., Thrombosis Res. 38: 417 (1985). 5. Bajaj, S.P., et al., J. Biol. Chem. 248: 7729 (1973). 6. Krishnaswamy, S., et al., J. Biol. Chem. 261: 8997 (1986). 7. Fujikawa, K., et al., Biochemistry 11: 4882 (1972). 8. Discipio, R.G., et al., Biochemistry 16: 698 (1977). 9. Discipio, R.G., et al., Biochemistry 18: 899 (1979). 10. Jackson, C.M., et al., Biochemistry 7: 4506 (1968). 11. McMullen, B.A., et al., Biochemistry 22: 2875 (1983).