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Pisum sativum agglutinin is nearly identical in structure and carbohydrate specificity to Lens culinaris agglutinin. PSA has four subunits, two of approximately 17,000 daltons and two of about 6,000 daltons. Isoelectric focusing has revealed two isolectins with isoelectric points of pH 5.9 and pH 7.0. The lectin has specificity toward a-linked mannose-containing oligosaccharides, with an N-acetylchitobiose-linked a-fucose residue included in the receptor sequence. Calcium and manganese ions are required for activity. PSA has been used to fractionate cells, to isolate glycoproteins and glycopeptides, to distinguish between normal and virally transformed cells, as a T-cell mitogen, and as an inhibitor of allograft rejection.
Agarose bound* Pisum Sativum Agglutinin is prepared from affinity-purified lectin. Heat stable, cross-linked 4% agarose beads with a molecular weight exclusion limit of about 2x107 are used as the solid-phase matrix to which the lectin is covalently bound. The attachment of the lectin to the solid phase is carefully controlled in order to preserve the activity of the lectin as well as to minimize conformational changes of the bound lectin which might result in nonspecific ionic or hydrophobic interactions. |