Chemical modification and sugar binding properties of two major lectins from Pinhao (Araucaria brasiliensis) seeds
1993
Datta, P.K. | Figueroa, M.O.R. | Lajolo, F.M.
Araucaria brasiliensis lectins, lectin I and lectin II, were subjected to various chemical modifications to d etect the amino acid residues present in their carbohydrate binding sites. Modification of tyrosine and arginine residues did not affect binding activities of lectins. However, modification of tryptophan and histidine led to a complete loss. Modification of amino and carboxyl groups of both lectins also abolished completely their hemaggluti nating capacity. The carbohydrate moiety of lectins was not involved in maintaining their hemag glutinating activities. Binding of monosaccharides was studied by UV difference spectroscop y which showed that both lectins have two binding sites with different affinities for sugars. Eac h lectin molecule may bind from 6 to 14 sugar residues. The association constants and free ener gy of binding for different sugars are presented.
显示更多 [+] 显示较少 [-]