Human Factor XII (XII) (Hageman Factor) is a single chain (78kD) glycoprotein zymogen that circulates in plasma at a concentration of 40 mg/ml.
Reciprical activation of XII to the active serine protease factor XIIa (XIIa) by kallikrein is central to initiation of the intrinsic coagulation pathway.
Surface bound a-XIIa in turn activates factor XI to XIa.
A single cleavage by kallikrein at R353-Val354 of XII yields a-XIIa, a 2 chain protease (80kD) held together by disulfide bonds.
The COOH-terminal light chain (28kD) contains the catalytic triad (His-40, Asp-89, Ser-191), while the NH2-terminal heavy chain (52kD) conatins the anionic surface binding portion of the molecule.
A secondary cleavage of a-XIIa by kallikrein outside the disulfide bond yields b-XIIa (XIIf, BHFa, HFf, hageman factor fragments) (28kD), which no longer binds anionic surfaces.
b-XIIa can activate prekallikrein, but has little procoagulant activity.
Inhibitors of XIIa include C1-INH, a2-antiplasmin, a2-macroglobulin and antithrombin III.
At physiological concentrations, the relative effectiveness of these inhibitors is 91: 4.5:3:1.5, respectively.
The ratio of C1-INH to XII has been implicated in the “cold activation” of factor VII and the conversion of prorenin to renin on storage of plasma.
Applications:Suitable for use in ELISA, Inhibition and Coagulation assays.
Other applications not tested.
Recommended Dilutions:Optimal dilutions to be determined by the researcher.
Storage and Stability:May be stored at 4°C for short-term only.
Aliquot to avoid repeated freezing and thawing.
Store at -20°C.
Aliquots are stable for 12 months after receipt.
For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：250ug
Host：mouse
Source Antibody：human
Grade：Affinity Purified
Purity：Purified by Protein G affinity chromatography from ascites.
Form：Supplied as a liquid in PBS, pH 7.4. No preservative added.
Specificity：Recognizes the light chain of human Factor XII and at 100nM inhibits 50% of Factor XII activity.
