Chemical and gel electrophoretic characterization of acetylated faba bean protein isolates

Abstract

AbstractThe extent of modification of amino and hydroxyl groups in acetylated faba bean protein isolates was determined. Gel electrophoretic studies of unmodified and acetylated faba bean legumin and protein isolates were carried out in acidic and alkaline buffer systems as well as in a SDS‐containing system.A remarkable increase of O‐acetylation was found after the N‐acetylation has reached a degree of about 60%. Structure changes of the proteins were indicated from the gel electrophoresis patterns in the same region of modification. The quantity of acetyl residues fixed on hydroxyl groups in exhaustively modified protein isolates corresponds to 40 % of the total amount of acetyl groups introduced into the proteins.The SDS electrophoresis of the acetylated legumin and protein isolates revealed a remarkable increase of the molecular mass of the acidic α‐polypeptide chains only, which is an experimental proof of a preferential acetylation of the latter ones. This gives confirmation of the structural model in which the α‐chains are proposed to be situated on the surface of the protein.