Complement Factor I (FI) is a serine protease, essential for the regulation of the complement system, and is encoded by the FI gene on chromosome 4. Known as the C3b/C4b inactivator, FI plays a crucial role in modulating complement activation by cleaving C3b and C4b in both cell-bound and fluid phases. Predominantly synthesized in the liver, FI begins as an 88 kDa
precursor protein that is processed into its active form—a disulfide-linked dimer composed of a 51 kDa heavy chain and a 37 kDa light chain.
Genetic diversity in the FI gene, including polymorphisms like R201S, R406H, and R502L, contributes to variations in FI function. A deficiency in FI can lead to decreased plasma levels of complement component 3 (C3), due to unchecked activation of the complement alternative pathway. This can result in recurrent bacterial infections, particularly in children. Additionally, recent findings have implicated mutations in the FI gene in the pathogenesis of Haemolytic Uremic Syndrome, a serious renal condition also linked to uncontrolled complement activity.
This product is manufactured in Netherlands by Hycult Biotech.
| Size | 1 x 96 Well |
| Sensitivity | 1.56 ng/mL |
| Dynamic Range | 1.56 – 100 ng/mL |
| Incubation Time | 1 hour 15 minutes |
| Sample Type | Plasma, Serum |
| Storage | 2-8°C |
| Alternative Names | CFI, C3b/C4b Inactivator |