Complement C4 (C4) plays a central role in both the classical and lectin pathways of complement activation, with levels in human plasma ~0.4 mg/ml. C4 circulates in human plasma as a heterotrimer of 205,000 Da in plasma. The three disulfide-linked chains have molecular weights of 93 (alpha), 75 (beta), and 32 (gamma) kDa. These are readily processed to create C4a, C4b or C4c depending on the processed state.
Purity: ≥85% by SDS-PAGE.
Reacts to C4 antisera on Western Blot
Not biologically active.
Prepared from plasma shown to be non reactive for HBsAg, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA-required tests.
Precursor of non-enzymatic components of the classical, lectin and GZMK complement pathways, which consist in a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system.