Purification, characterisation, and carbohydrate specificity of the lectin of Ficus cunia.
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 M(r) 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-->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-->4)/(1-->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.
Ray
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Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Calcutta.
Ahmed
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H
Basu
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Chatterjee
B P
BP
D000818:Animals; D001212:Asialoglycoproteins; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides; D004591:Electrophoresis, Polyacrylamide Gel; D060748:Fetuins; D006020:Glycopeptides; D006384:Hemagglutination; D006801:Humans; D005779:Immunodiffusion; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides; D014407:Tumor Cells, Cultured; D000509:alpha-Fetoproteins
D001212:Asialoglycoproteins; D002241:Carbohydrates; D004187:Disaccharides; D060748:Fetuins; D006020:Glycopeptides; D037102:Lectins; D009844:Oligosaccharides; D000509:alpha-Fetoproteins; C017029:asialofetuin