Recombinant Human Factor IX Protein (C-His)

Measured by functional ELISA. Immobilized recombinant human factor IX binds reference anti-factor IX antibodies with EC50 values in the ng/mL range.

Coagulation factor IX is a vitamin K-dependent serine protease zymogen of the intrinsic pathway; its genetic deficiency causes hemophilia B, one of the classic inherited bleeding disorders. The mature protein organizes a Gla domain (γ-carboxylated for membrane binding), two EGF-like domains, an activation peptide and a catalytic protease domain — a modular architecture that has made FIX a flagship of modern hemophilia care, from engineered replacement products and gene therapy (Octaplas/fidanacogene elaparvovec lineage) to bispecific antibodies mimicking its cofactor function. Mammalian-cell-expressed recombinant factor IX preserving γ-carboxylation supports inhibitor-antibody assays, pharmacokinetic research and cascade modeling.