Separation and partial characterization of isolectins with different subunit compositions from Datura stramonium seeds

AbstractThe lectin from Datura stramonium seeds was separated into three individual isolectins by hydrophobic-interaction chromatography on phenyl-Sepharose. Two of these isolectins are homodimers made up of two A- or two B-subunits, whereas the third is a heterodimer composed of one A- and one B-subunit. Analysis of the homodimeric AA- and BB-isolectins revealed that the A- and B-subunits have similar but not identical Mr values (32 000 and 28 000, respectively), amino acid and carbohydrate compositions. The A-subunit has a higher affinity for N-acetyl-D-glucosamine oligomers than the B-subunit, whereas the latter is more specific for the carbohydrate determinants of some animal glycoproteins such as fetuin, asialofetuin and ovomucoid