SUBUNIT GLYCOSYLATION OF LUPINUS-ANGUSTIFOLIUS SEED GLOBULINS

Reduced polypeptide subunits of α-, β- and γ-conglutins from Lupinus angustifolius seeds were resolved by preparative SDS gel electrophoresis of the fluorescent labelled proteins, into four, six and two major components, respectively. All subunits were glycosylated, to varying degrees, containing mannose, galactose and glucosamine. The major glycopeptides released by pronase digestion of each conglutin had similar galactose/mannose ratios; the MW of the glycopeptide released from α- and β-conglutin was ca 5000. Although on average, each molecule of α-conglutin contains one main oligosaccharide chain, and β-conglutin two, the presence of carbohydrate in all polypeptide subunits suggests that some subunits may arise by proteolytic cleavage of a larger polypeptide after glycosylation. The presence of minor glycopeptide components indicates that modification of carbohydrate chains during seed development may also occur. © 1979.