39D-17

E. Gonzalez de Mejía¹, N. E. ROCHA-GUZMáN¹, L. A. Salazar-Olivo, and I. Goldstein. (1) Departamento de Investigación y Posgrado en Alimentos, Universidad Autónoma de Querétaro, Centro Universitario Cerro de las Campanas, Facultad de Química, Querétaro, 76010, Mexico

Lectins are non-immune proteins or glycoproteins that bind to specific carbohydrates expressed on the cell surface with high affinity. Because of their binding specificity, they have the capability to serve as recognition molecules between normal and transformed cells. It is assumed that lectins play fundamental biological roles in plants because they are found in different organs and tissues. We have identified four sources of lectins in crude extracts of legumes (Phaseolus vulgaris, Phaseolus acutifolius type wild and cultivated, Prosopis juliflora) with biological activity on transformed cells. Our objective was purify a lectin with capability to inhibite biological activities on transformed cells without affect normal cells. Crude extracts of Prosopis juliflora had the capability to inhibite the proliferation of HeLa cells in a 90 % when concentrations of 50 µg/ml of protein was used, crude extracts of common bean showed an inhibition on proliferation about 30 %. Crude extracts of Phaseolus acutifolius type wild and cultivated did not show inhibition effect. A lectin from crude extracts of Prosopis juliflora seeds was purified by affinity chromatography in order to know its biological effect on proliferation of normal and transformed human cells and the effect on platting eficiency and cell adhesion. Lectin from Prosopis juliflora seeds (PJL) showed specificity to glycoconjugates whose glycosidic residue was galactosil b 1, 3 NAcGal. It had a molecular weight of 50,000 Da with two subunits (18,000 Da and 32,000 Da) and to create agglomerates of 600,000 Da with biological activity. PJL to concentrations up to 20 m g/ml inhibited proliferation and clonal growth of HeLa cells. It favored cell adhesion of these cells without affect proliferation and clonogenicity of human keratinocytes to a concentration of 50 m g/ml of protein. PJL has a differential effect between normal and transformed cells, with the possibility of being used in cancer studies.