A C4BP measurement is the quantification of C4BP, it controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. Alpha chain binds C4b. It interacts also with anticoagulant protein S and with serum amyloid P component. (Uniprot defintion).
Buil et al, 2010 propose that C4BP may be a susceptibility locus for venous thrombosis based on GWAS and gene expression studies. The trait is C4BP measurement (EFO_0004572). Also known as: C4b binding protein levels, C4b-binding protein levels, C4b-binding protein measurement.