Protein C, Activated, Dansyl EGR, Bovine (APC)

Activated protein C (APC) is an anticoagulant serine protease derived from the two chain, vitamin K-dependent zymogen, protein C (3-7). A complex between alpha-thrombin and thrombomodulin catalyzes a single cleavage at Arg-12 (Arg-14 in bovine) in the heavy chain of protein C, to generate activated Protein C. Several non-physiologically relevant proteases such as RVV-X activator, trypsin, and PROTAC are also capable of activating protein C. APC functions as an anticoagulant which catalyzes the proteolytic inactivation of the cofactors, factors Va and VIIIa, leading to inhibition of the prothrombinase and factor Xase complexes. The inactivation of factors Va and VIIIa is both Ca2+ and phospholipid dependent. The vitamin K dependent cofactor, protein S, moderately increases this rate of inactivation by forming a 1:1 complex with APC (Kd=6x10-9M) (8). \n\nSeveral factors attenuate the anticoagulant activity of APC. Factor Xa protects factor Va from proteolysis by APC by competing for a similar binding site on factor Va. Thrombin has also been proposed as a regulator of APC by proteolytic inactivation of protein S. In addition, APC is regulated by a circulating heparin-dependent protein C inhibitor (PAI-3), a circulating heparin-independent protein C inhibitor, a platelet-derived protein C inhibitor, and PAI-1. The complexes formed between APC and both types of PAI have been reported to account for increased fibrinolysis observed upon infusion of APC or the generation of APC in vivo. \n\nLocalization: Plasma\n\nMode of Action: Anticoagulant, inactivates factors Va and VIIIa\n\nExtinction Coefficient: E1%1cm, 280nm = 13.7 (9)\n\nIsoelectric Point: 4.2-4.5 (9)\n\nStructure: Two chains, Mr=35,000 and 21,000, disulfide linked, NH2-terminal gla domain two EGF domains\n\nPercent carbohydrate: 14% (5)\n\nPost-translational Modifications: Eleven gla residues, one beta-hydroxyaspartate\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 6 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

P9081-05

Size

50ug

Form

Supplied as a liquid 20mM Hepes, pH 7.4, 150mM sodium chloride.

Purity

Purified by Ion Exchange chromatography (~95% SDS-PAGE).

References

1. Kalafatis, M., and Mann, K.G., J. Biol. Chem., 268, 27246 (1993), 2. Kalafatis, M., et al., J. Biol. Chem., 269, 31869 (1994), 3. Esmon, C.T., Progress in Thromb. and Hemostas., 10, 25 (1984), 4. Esmon, C.T., J. Biol. Chem., 264, 4743 (1989), 5. Kisiel, W., et al., Methods Enzymol., 80, 320 (1981), 6. Stenflo, J., Semin. in Thromb. and Hemostas., 10, 109 (1984), 7. Marlar, R.A., Semin. in Thromb. and Hemostas., 11, 387 (1985), 8. Walker, F.J., et al., J. Biol. Chem., 256, 11128 (1981), 9. Discipio, R.G., et al., Biochemistry, 18, 899 (1979),10. Dahlback, B., and Hildebrand, B., Proc. Natl. Acad. Sci. USA, 91, 1396 (1994). 11. Svensson, P.J., and Dahlback, B., New Engl. J. Med., 330, 517 (1994). 12. Hwang, K., Arthritis Rheum. 2003 June ; 48(6): 1622-1630. (used as capture in ELISA). 13. Raife, T., et al., J Clin Invest. 1994 April; 93(4): 1846-1851. (used as standard in aPC generation). 14. Schuepbach, R., et al., Blood. 2008 March 1; 111(5): 2667-2673. (PAR1 cleavage). 15. Adams, T., Hockin, M., Mann, K., Everse, S., Proc Natl Acad Sci USA. 2004 June 15; 101(24): 8918-8923. (bovine aPC used to inactivate bovine Va). 16. Gale, A. et al., J. Biol. Chem. (2008) 283(24) 16355-16362. (Inactivation of VIIIa).