concanavalin-a and chloroacetamide

Irradiation of tetrameric concanavalin A with a high-pressure mercury lamp in the presence of chloroacetamide and fractionation of the reaction product by affinity chromatography gave a lectin derivative showing a monomeric molecular weight at pH 7.4, with an overall yield of 25%. It retained the intact binding ability against methyl-alpha-D-glucopyranoside. Hemagglutination and glycogen precipitation data suggested the monovalent nature of the derivative. The results of amino acid composition analyses indicated that the photochemically induced alkylation at one or two tryptophan residues per subunit of concanavalin A may be responsible for the dissociation into monovalent monomers which are stable at physiological pH.

Topics: Acetamides; Alkylation; Amino Acids; Chemical Precipitation; Concanavalin A; Glycogen; Hemagglutination; Light; Macromolecular Substances; Methylglucosides; Molecular Weight; Photochemistry