Recombinant Human Complement Factor H (aa 860-1231), CF

Recombinant Human Complement Factor H (aa 860-1231), CF Summary

Product Specifications

Product Datasheets

Carrier Free

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: Complement Factor H

Complement Factor H is a 155 kDa glycoprotein that provides critical negative regulation to the alternative pathway of complement cascade. It is secreted by Kupffer cells, hepatocytes, vascular endothelial cells, and platelets, and circulates in the serum at high concentration (1). Complement Factor H is composed of 20 SCRs (short consensus repeats), each of which consists of approximately 60 amino acids with four invariant Cys residues (2). Alternate splicing generates an isoform that is truncated following SCR7. Complement Factor H interacts with cell surface polyanions including heparin and sialoglycoproteins (3 - 6), and immobilized Complement Factor H supports the CD11b/CD18 integrin-dependent adhesion of neutrophils (7). It prevents local complement activation by sequestering complement component C3b, accelerating the decay of C3 and C5 convertases, and functions as a cofactor for the C3b inactivator, Factor I (1, 3, 6, 8). The recombinant protein expressed here corresponds to SCR15-20, which encompass the primary binding sites for heparin and C3b, as well as for the peptide hormone adrenomedullin (4, 9 - 11). Within SCR15-20, human Complement Factor H shares 60% and 63% amino acid sequence identity with mouse and rat Complement Factor H, respectively. Dozens of mutations clustered in SCR15-20 are associated with atypical hemolytic uremic syndrome, a disorder characterized by anemia, thrombocytopenia, and renal failure (12). Binding of Complement Factor H to tumor cell-associated dentin matrix protein 1, bone sialoprotein, or osteopontin results in the protection of that cell from complement-mediated lysis (13, 14). A variety of pathogenic microbes also express Complement Factor H binding molecules that interfere with immune clearance of the infection (15).

Related Research Areas

• Complement Pathway
• Serine Proteases and Regulators