Detection and characterization of a lectin from non-seed tissue ofPhaseolus vulgaris

The distribution of lectin in various tissues ofPhaseolus vulgaris L. (cv. red) has been investigated using a sensitive solid-phase enzyme immunoassay. Roots, leaves and stems from 3- to 4-week-old plants were screened for their lectin content; low levels could be detected in all organs, with a relative distribution of 37% in roots, 20% in leaves and 43% in stems. The lectin from stemsleaves and roots was then isolated from 5- to 6-week-old plants using extraction, salt fractionation and affinity chromatography on immobilized porcine thyroglobulin. A comparative study of the seed lectin and the lectin isolated from 5- to 6-week-old plants was made using hemagglutination, inhibition of hemagglutination, immunodiffusion, polyacrylamide and agarose electrophoresis. The results showed that lectin isolated from the different tissues was immunologically identical and exhibited the same subunit structure and similar isolectin composition as the seed lectin.