Factor XI Polyclonal Antibody – Affinity Purified – Sheep
Affinity’s Factor XI Polyclonal Antibody – Affinity Purified – Sheep is the highest level of our Factor XI antibody family. During the Antigen Affinity Purification process the IgG has had any non-specific immunoglobulin fraction eliminated which enriches the specificity of the remaining immunoglobulin towards the target antigen. The result is a very high-purity product with a substantially higher titre than whole or purified IgG. Our Factor XI Polyclonal Antibody – Affinity Purified – Sheep is provided in a solution of HEPES buffered saline containing 50% glycerol (v/v) and is intended for applications such as immunoblotting, immunostaining of cells and several types of immunoassays where the higher signal-to-noise ratio achieved with this enriched product is required.
Product Code: SAFXI-AP
Retail Product Size: 0.5mg vial
Host Animal: Sheep Anti-Human Factor XI Polyclonal Antibody – Affinity Purified
Species Cross Reactivity: View Chart
Product Datasheet: Factor XI F11 Polyclonal Antibody, affinity purified anti-human sheep IgG
Description of Factor XI (FXI)
Factor XI (FXI, plasma thromboplastin antecedent) is a coagulation protein produced in the liver that circulates in plasma at approximately 5 μg/mL (30 nM). The mass of FXI is 160 kDa as determined by SDS-PAGE under non-reducing conditions and 80 kDa upon reduction. FXI consists of two identical 80 kDa subunits linked by disulphide bonds. Each subunit consists of a tandem repeat of four apple domains followed by a serine protease catalytic domain. Cleavage of FXI by activated factor XII or thrombin converts each subunit into a two-chain form and generates two active sites per FXIa molecule. The mass of FXIa is 160 kDa unreduced, but upon reduction FXIa migrates as a heavy chain of 50 kDa and a light chain of 30 kDa. The catalytic site of FXIa resides in the light chain. In plasma, FXI or FXIa circulates in non-covalent 1:1 complex with high molecular weight kininogen, which acts as a cofactor in the activation of FXI by activated factor XII. The activity of FXIa is regulated by platelets and by several proteinase inhibitors including, in order of decreasing importance, C1-inhibitor, α2antiplasmin, α1antitrypsin and antithrombin. Heparin has relatively little effect on the rate of inhibition of FXIa by antithrombin. The only known natural substrate for activated FXI (FXIa) is factor IX (Christmas factor) and the only cofactor required for this reaction is ionized calcium1-3.
References and Review
- Wuillemin WA, Minnema M, Meijers JCM, Roem D, Erenberg AJM, Nuijens JH, ten Cate H, Hack EC; Inactivation of Factor XIa in Human Plasma Assessed by Measuring Factor XIa-Protease Inhibitor Complexes: Major Role for C1-Inhibitor. Blood 85:1517, 1995.
- DeLa Cadena R, Watchtfogel YT, Colman RW, in Hemostasis and Thrombosis, 3rd Edition, eds. RW Colman, J Hirsh, VJ Marder and EW Salzman, pp. 219-240, J.B. Lippincott Co., Philadelphia, 1994.
- Baglia FA, Seaman FS, Walsh, PN; The Apple 1 and 4 domains of Factor XI Act to Synergistically Promote the Surface-Mediated Activation of Factor XI by Factor XIIa. Blood 85:2078, 1995.