Prekallikrein (Fletcher Factor), human
|Antibody||Host||Catalogue No.||Size||Product Insert|
|Purified IgG||Sheep||SAPK-IG||10 mg|
|Affinity purified IgG||Sheep||SAPK-AP||0.5 mg|
|Affinity purified, peroxidase conjugated IgG||Sheep||SAPK-APHRP||0.2 mg|
|Matched Pair Antibodies for EIA||PK-EIA||4 plates|
Description of Prekallikrein (PK)
Prekallikrein (PK), previously known as Fletcher Factor, is a single chain glycoprotein produced in the liver. The plasma concentration of PK is 50 Î¼g/ml (550 nM), approximately 75% of which circulates in complex with high molecular weight kininogen (HK) and the remainder as free PK. Plasma PK is heterogeneous in both mass and charge due to variable degrees of glycosylation. Approximately 90% of plasma PK has an apparent molecular weight of 88 kDa as determined by SDS-PAGE and the remaining 10% has an apparent mass of 85 kDa. The catalytic site resides in the light chain. The heavy chain of PK contains four apple-domain structures similar to those found in FXI and these are required for binding of PK to HK. PK is the zymogen form of the enzyme kallikrein, which is involved in the proteolysis of kininogens with subsequent release of bradykinin, a potent vasodilator. PK participates in the contact phase of coagulation as a substrate for surface-bound activated factor XII (FXIIa) in the presence of the cofactor HK. As PK and factor XI (FXI) both circulate in complex with HK, both are localized to activating surfaces through their respective binding to HK. Limited proteolysis of PK by FXIIa generates kallikrein, a two-chain serine protease that initiates the reciprocal activation of PK and FXI. Kallikrein activity in plasma is regulated predominantly by C1-Inhibitor and Î±2macroglobulin, with relatively minor contributions by Protein C Inhibitor, Î±2antiplasmin, and antithrombin1-3.
1. Coleman RW, Schmaier AH; Contact System: A Vascular Biology Modulator With Anticoagulant, Profibrinolytic, Antiadhesive and Proinflammatory Attributes. Blood 90, pp 3819-3843, 1997.
2. 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.
3. Hojima Y, Pierce JV, Pisano JJ; Purification and Characterization of Multiple Forms of Human Plasma Prekallikrein. JBC 260, pp 400-406, 1985.
SAPK-HRP Sheep anti-human Prekallikrein, peroxidase labelled IgG
PK-EIA Matched-Pair Antibody Set for ELISA 5×96 wells
PK-DP Human plasma deficient in Prekallikrein, immune depleted, Frozen
PK-LDP Human plasma deficient in Prekallikrein, immune depleted, Lyophilized