Factor VIIIc (Antihaemophilic Factor)

Factor VIII (antihemophilic globulin and Factor VIII:C) is a large glycoprotein (320kD) that circulates in plasma at ~200ng/ml. Synthesized in the liver, the majority of Factor VIII is cleaved during expression, resulting in a heterogeneous mixture of partially cleaved forms of F.VIII ranging in size from 200-280kD. The F.VIII is stabilized by association with von Willebrand Factor to form a F.VIII-vWF complex required for the normal survival of F.VIII in vivo (t1/2 of 8-12 hours). F.VIII is a pro-cofactor that is activated through limited proteolysis by thrombin. In this process F.VIIIa dissociates from vWF to combine with activated Factor IX, calcium and a phospholipid surface where it is an essential cofactor in the assembly of the Factor X activator complex. Once dissociated from vWF, F.VIIIa is susceptible to inactivation by activated Protein C and by non-enzymatic decay.\nHemophilia A is a congenital bleeding disorder resulting from an X-chromosome-linked deficiency of F.VIII. The severity of the deficiency generally correlates with the severity of the disease. Some Hemophiliacs (~10%) produce a F.VIII protein that is partially or totally inactive. The production of neutralizing antibodies to F.VIII also occurs in 5-20% of Hemophiliacs (1-3).\n\nApplication:\nSuitable for use in ELISA, Immunoelectrophoresis and Neutralization. Other applications not tested.\n\nRecommended Dilution:\nNeutralization: 420 Bethesda Units/ml IgG against normal plasma (4). One Bethesda unit/ml is defined as the amount of inhibitor that resulted in 50% residual F.VIII activity after 2 hours at 37C.\nOptimal dilutions to be determined by the researcher.\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 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.

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SPECIFICATIONS

Catalog Number

F0016-30

Size

1mg

Applications

ELISA

Hosts

Sheep

Reactivities

Hum

Form

Supplied as a liquid in 10mM HEPES, pH 7.4, 0.15M sodium chloride, 50% glycerol.

P Type

Pab

Purity

Purified by caprylic acid and ammonium sulfate precipitations, and solid-phase adsorption to remove unwanted crossreactivity.

Isotype

IgG

References

1. Lollar P, Fay PJ, Fass DN; Factor VIII and Factor VIIIa. Methods in Enzymology, 222:122, 1993. 2. Hoyer, LW, Wyshock EG, Colman RW, in Hemostasis and Thrombosis, 3rd Edition, eds. RW Colman, J Hirsh, VJ Marder and EW Salzman, pp. 109-133, J.B. Lippincott Co., Philadelphia, 1994. 3. Pittman DD, Kaufman RJ. Structure-Function Relationships of Factor VIII Elucidated through Recombinant DNA Technology. Thromb. Haemostas. 61:161-165, 1989. 4. Kasper CK et al, Proceedings: A more uniform measurement of factor VIII inhibitors. Thromb Diath Haemorrh. 34:612,1975. 5. Kasper CK and Pool JG. Letter: Measurement of mild factor VIII inhibitors in Bethesda units. Thromb Diath Haemorrh 34:875,1975.

Additional Info

Recognizes human F.VIII as demonstrated by immunodiffusion and ELISA. No reactivity was observed with von Willebrand Factor.