Purification, characterisation, and carbohydrate specificity of the lectin of Ficus cunia
1993
Ray, S. | Ahmed, H. | Basu, S. | Chatterjee, B.P.
A lectin, isolated from the seeds of Ficus cunia and purified by affinity chromatography on fetuin-Sepharose, was homogeneous in PAGE, GPC, HPLC, and immunodiffusion, and had mol wt of 3200-3500. In SDS-PAGE and HPLC in the absence and presence of 2-mercaptoethanol, the lectin gave a single band or peak corresponding to Mr 3300-3500, thus indicating it to be a monomer. The lectin agglutinated human erythrocytes regardless of blood group, bound to Ehrlich ascites cells and to human rat spermatozoa, and was thermally stable; its activity was enhanced by Ca2+. The lectin is a metalloprotein that was inactivated by dialysis with EDTA followed by acetic acid, but reactivated by the addition of Ca2+. The lectin contained 2.0% of carbohydrates. large proportions of acidic amino acids, but little methionine. In hapten-inhibition assays, chitin oligosaccharides [(1 leads to 4)-linked beta-GlcNAc] and N-acetyl-lactosamine were inhibitors of which N,N',N'',N'''-tetra-acetylchitotetraose was the most potent. Among the macromolecules tested that contain either multiple N-acetyl-lactosamine and/or (1 leads to 4)/(1 leads to 6)-linked beta-GlcNAc, asialofetuin glycopeptide was the most potent inhibitor. Thus, an N-acetyl group and substitution at C-1 of D-GlcN are necessary for binding.
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