IDENTIFICATION AND BIOLOGICAL-ACTIVITY OF LECTINS OF DIFFERENT SUBUNIT COMPOSITION ISOLATED FROM PHASEOLUS-VULGARIS L VAR ATHROPURPUREA

Protein concentrate, albumin (AF) and globulin fractions (GF) (60.2, 4 2.3 and 69.7% of protein content, N x 5.40, respectively) were obtaine d from raw seeds of Phaseolus vulgaris var athropurpurea (PHVa) cultiv ated in northern Spain. SDS-PAGE analysis revealed that the isolectins were present solely in the AF while the GF was entirely lectin-free. Affinity chromatography and SDS-PAGE were used to separate and identif y lectins of different subunit composition: E(4) + E(3)L, E(2)L(2), El (3) and L(4) (in g: 0.12, 0.03, 0.03 and 0.44, respectively, from 2.9g of PHVa meal). In this cultivar the amount of E(4) was negligible. Wi th the methodology followed in this study the L(4) isolectin could not be isolated from the AF and it was determined by densitometry. The bi ology activities of these PHVa phytohaemagglutinins-erythroagglutinati ng and lymphocyte transformation activities-were assessed in rat and h uman cells. There was a direct correlation between the erythroagglutin ating activity and the E subunit composition of the isolectins using r at red blood cells. The lymphocyte transformation activity of the isol ectins with human peripheral blood lymphocytes was correlated with the L-subunit content in the lectins. However, the relationship between l ymphocyte transformation activity and lectin profile with rat lymphati c node lymphocytes was not as straightforward as expected.