CFI Human
Human Plasma.
Complement factor I, C3B/C4B inactivator, CFI, IF.
Sterile filtered solution.
Greater than 93.0% as determined by SDS-PAGE.
Description
Human Complement Factor I produced in Human plasma is glycosylated polypeptide composed of 2 disulfide-linked chains having a total molecular mass of 88kDa.
Product Specs
Complement Factor I (CFI) is a regulatory protein that plays a crucial role in the complement system, a part of the innate immune response. It inactivates key complement proteins C3b and C4b, preventing excessive complement activation. CFI requires a cofactor such as Factor H or C4b-binding protein for its activity. Upon binding to these cofactors, CFI cleaves the alpha chain of C3b and C4b, rendering them inactive (iC3b and iC4b). This cleavage inhibits their ability to participate in complement activation. CFI also cleaves iC3b in the presence of Complement Receptor 1 (CR1), releasing C3c from C3dg. C4b undergoes rapid cleavage at two sites, leading to the separation of C4c from C4d. These actions of CFI are essential for controlling complement activity and preventing damage to host tissues.
Human Complement Factor I, produced from human plasma, is a glycoprotein composed of two disulfide-linked chains. It has a molecular weight of 88kDa.
The product is a sterile-filtered solution.
The Complement Factor I protein solution is formulated in a sodium phosphate buffer with a pH of 7.2.
For optimal stability, keep Human Complement Factor I refrigerated at 4°C. If used within 2-4 weeks, the entire vial can be stored at this temperature. For prolonged storage, freeze the product below -20°C. Adding a carrier protein (0.1% HSA or BSA) is recommended for long-term storage. To maintain product integrity, avoid repeated freezing and thawing.
The purity of this product is greater than 93.0%, as determined by SDS-PAGE analysis.
The plasma used in the production of this product undergoes rigorous testing for viral contaminants. Each donor plasma sample is screened and confirmed negative for antibodies to HIV-1, HIV-2, Hepatitis C Virus (HCV), and Hepatitis B surface antigen (HBSAg).
Complement factor I, C3B/C4B inactivator, CFI, IF.
Human Plasma.
Product Science Overview
CFI was first isolated in 1966 from guinea pig serum . It is a soluble glycoprotein that circulates in human blood at an average concentration of 35 μg/mL . The gene encoding CFI is located on chromosome 4 (4q25) in humans . The protein is synthesized primarily in the liver, but also in monocytes, fibroblasts, keratinocytes, and endothelial cells .
When synthesized, CFI is a 66 kDa polypeptide chain with N-linked glycans at six positions . It is then cleaved by furin to yield the mature factor I protein, which is a disulfide-linked dimer consisting of a heavy chain (51 kDa) and a light chain (37 kDa) . Only the mature protein is active.
CFI plays a pivotal role in regulating complement activation by cleaving cell-bound or fluid phase C3b and C4b . This regulation is essential to prevent uncontrolled complement activation, which can lead to tissue damage. CFI requires cofactors such as Factor H, C4b-binding protein, and membrane cofactor protein to exert its proteolytic activity .
Deficiency in CFI can lead to severe immune system disorders. Complete deficiency is associated with recurrent bacterial infections due to uncontrolled activation of the complement system . Approximately 30 families with CFI deficiency have been described worldwide . Patients with CFI deficiency often exhibit low levels of C3 and suffer from recurrent bacterial infections .
CFI deficiency is typically inherited in an autosomal recessive manner . Molecular studies have identified various mutations in the CFI gene, including novel mutations and large gene deletions . These genetic variations can affect the protein’s function or concentration, leading to clinical manifestations of the deficiency .
Ongoing research aims to better understand the genetic and molecular mechanisms underlying CFI deficiency and to develop effective diagnostic and therapeutic strategies. The identification of novel mutations and the development of diagnostic flowcharts are crucial steps in improving patient outcomes .
