Lectin like properties and differential sugar binding characteristics of C-reactive proteins purified from sera of normal and pollutant induced Labeo rohita

Different forms of C-reactive proteins (CRPs) have been purified to electrophoretic homogeneity from the sera of Labeo rohita confined in freshwater (CRPN) and water polluted with nonlethal doses of cadmium (CRPCd) or mercury (CRPHg). CRPN, CRPCd, and CRPHg show remarkable differences in their electrophoretic mobility but exhibit strong immunological cross reactivity. All these CRPs exhibit variable agglutination properties with erythrocytes from diverse sources in presence of Ca+2, which could be inhibited by a variety of sugars showing specificity for galactose. Inhibition results show that the potency of galactose as an inhibitor increases about 4 fold in the process of transformation of CRPN to CRPCd and CRPHg. In case of CRPN, Gal beta(1-->1) Gal and oNO(2) phenyl beta-Gal show highest inhibitory potency while oNO(2)-phenyl beta-Gal is the most potent inhibitor for CRPCd and CRPHg but the potency of Gal beta(1-->1) Gal reduced drastically. 6-phosphate D-Gal and stachyose are 20 times weaker inhibitors than D-Gal for induced CRP mediated agglutination, in contrast, these sugars are only 6 times weaker for CRPN. Dissociation constants of the binding of CRPN with phosphoryl choline (PC) and galactose are about 9 mM and PC binding causes a change in the alpha and beta conformations of these CRPs.