Protein---carbohydrate interaction : Part XXI. The interaction of concanavalin a with d-fructans

Abstract

The immunochemical techniques of quantitative precipitation and hapten inhibition have been employed in a study of the interaction of concanavalin A with several levans of bacterial and plant origin. Of the polysaccharides that form a precipitate with concanavalin A (dextrans, -mannans, glycogens, amylopectins, and levans), levans appear to be the least reactive.Hapten-inhibition studies were conducted with a wide variety of compounds containing a furanoid ring. As a generalization, it may now be stated that all sugars containing the 1,4-anhydro--arabinitol moiety can bind to the active sites of concanavalin A. Because evidence from this laboratory suggests that the interaction of concanavalin A with reactive polysaccharides occurs at the same binding sites of the protein, reaction with levans may be rationalized on the basis of common configurational features. The disposition of the hydroxyl groups on C-3, C-4, and C-6 (or C-1, C-3, and C-4) of the [beta]--fructofuranosyl moeity, which is the residue that occurs at chain ends of levans, is similar to that on C-3, C-4, and C-6 of the [alpha]--glucopyranosyl moeity, the sugar residue found at the chain ends of [alpha]--glucans.