Fibrinogen Gamma (FGg) is a component of fibrinogen, a blood-borne glycoprotein comprised of three pairs of nonidentical polypeptide chains. Following vascular injury, fibrinogen is cleaved by thrombin to form fibrin which is the most abundant component of blood clots. In addition, various cleavage products of fibrinogen and fibrin regulate cell adhesion and spreading, display vasoconstrictor and chemotactic activities, and are mitogens for several cell types. FGg can be polymerized with fibrinogen (FGA) and fibrinogen (FGB) to form an insoluble fibrin matrix, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human FGg and recombinant mouse FGA. Briefly, FGg was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to FGA-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-FGg pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μL stop solution to the wells and read at 450/630 nm immediately. The binding activity of recombinant human FGg and recombinant mouse FGA was shown in Figure 1, the EC50?for this effect is 0.9 ug/mL.