Binding reactivity of C-reactive protein for polycations. II. Modulatory effects of calcium and phosphocholine.
C-reactive protein previously was shown to selectively and reversibly precipitate with certain small polymers of arginine and lysine. In the present report, calcium was shown to inhibit this reactivity in a dose-dependent manner, in direct contrast to the requirement for calcium for precipitation of CRP with C-polysaccharide. However, in the presence of phosphocholine, CRP rapidly precipitated and formed stable complexes with the polycationic polymers in the otherwise inhibitory calcium concentrations. alpha-Glycerol-phosphocholine, unlike phosphocholine, did not reverse this inhibitory effect. These results extend the characterization of the binding reactivity of CRP for polycations and suggest a relationship between this binding site and the sites for calcium and phosphocholine. We propose that CRP-polycation interactions in the presence of phosphocholine may have physiologic significance during the acute inflammatory process.
D001665:Binding Sites; D002097:C-Reactive Protein / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002412:Cations; D011232:Chemical Precipitation; D002794:Choline / Q000031:analogs & derivatives*; D005997:Glycerylphosphorylcholine / Q000494:pharmacology; D006801:Humans; D010455:Peptides / Q000494:pharmacology; D010767:Phosphorylcholine / Q000494:pharmacology*; D011107:Polylysine / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology
D002412:Cations; D010455:Peptides; D011108:Polymers; D010767:Phosphorylcholine; D011107:Polylysine; C015462:polyarginine; D005997:Glycerylphosphorylcholine; D002097:C-Reactive Protein; D002794:Choline; D002118:Calcium