【项目简介】
Human TFPI, also known as lipoprotein-associated coagulation inhibitor (LACI) and extrinsic pathway inhibitor (EPI), is a physiological inhibitor of extrinsic pathway of coagulation and has biological functions of anticoagulation and anti-inflammation. It is a secreted protein with a N-terminal acidic region, three Kunitz (K) domains separated with by two linker regions, and a C-terminal basic region. The first K domain (residues 54 to 104) inhibits coagulation factor VIIa complexed to tissue factor (TF). The second K domain (residues 125 to 175) inhibits factor Xa. The third K domain (residues 217 to 267) binds to heparin. The C-terminal basic region may have several functions. For example, it plays an important role in binding of TFPI to cell surfaces. The purified Recombinant Human TFPI ends at residue 282 and does not contain the last 20 residues (residues 283 to 302) in the C-terminal region. 

【检验原理】
本试剂盒采用双抗体夹心ELISA法。酶标微孔板上预包被有抗人TFPI抗体，当加入标准品和待测样本时，标准品和待测样本中的人TFPI会和该抗体结合。洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的的抗人TFPI抗体可与被酶标板捕获的人TFPI结合，形成“包被抗人TFPI抗体+人TFPI+抗人TFPI抗体-HRP”免疫复合物。当加入TMB显色底物后，复合物上连接的HRP催化底物反应，生成蓝色产物，终止反应后变为黄色。在450nm处测定OD值，人TFPI浓度与OD450值之间呈正比，可通过绘制标准曲线求出标本中人TFPI的浓度。