Table 1: Comparison of the properties of the pentraxins: C-reactive protein (CRP) and serum amyloid P (SAP).

C-reactive protein (CRP)Serum amyloid P (SAP)

Fc receptor bindingYesYes
Calcium-dependent ligand bindingYesYes
Complement activation through C1qYesYes
LigandsPhosphocholine
snRNP (Sm, RNP)
Histones
Apoptotic cells
Oxidized LDL
Phosphoethanolamine
DNA, chromatin
Heparin
Apoptotic cells
Amyloid fibrils
Major synthetic siteLiverLiver
InducersIL-6 (acute phase reactant) Constitutive
StructureCyclic pentamer 115,135 Da
Each subunit 23,027 Da
206 amino acids
Cyclic pentamer 127,310 Da
Each subunit 25,462 Da
204 amino acids
Glycosylation NoYes
Chromosomal location1q23.21q23.2