EVIDENCE FOR THE PHOSPHORYLATION AND GLYCOSYLATION OF THE AMARANTH 11S GLOBULIN (AMARANTHIN)

A series of 11S globulins isolated and purified from genetically diffe rent Amaranthus lines were found to be both glycosylated and phosphory lated to varying degrees, i.e., 4.0-7.8% and 0.030-0.058%, respectivel y. Carbohydrate was found to be N-linked to amino acids in the amarant h globulin and was composed of 28.0% xylose, 34.4% mannose 8.3% galact ose and 29.3% glucose whereas phosphate was found to be O-linked with six residues per globulin molecule. Both co- or post-translational mod ifications were found to influence the hydrophilicity, surface charge characteristics and stability of the secondary conformation of the glo bulin. Glycosylation was shown to be important in the folding and asse mbly of the globulin, whereas phosphorylation was found to enhance the metal-binding capacity of the globulin.