C-reactive protein in the rabbit: Isolation, characterization and binding affinity to phosphocholine☆

Abstract Several structural and functional characteristics of rabbit C-reactive protein have been established. The protein has been isolated by affinity chromatography on pneumococcal C-polysaccharide linked to agarose. Following gel filtration, SDS-polyacrylamide gel electrophoresis indicated a subunit size of 22,900 ± 400 daltons. Equilibrium gel filtration demonstrated a stoichiometric binding of ( 14 C) phosphocholine with an association constant ( K = 1.02 × 10 6 M −1 at 5°C and 0.62 × 10 6 M − rat 15°C in the medium range for antibody-hapten interactions. The amino acid composition for rabbit C-reactive protein is reported and compared with human C-reactive protein.