PURIFICATION AND CHARACTERIZATION OF THE RIBOFLAVIN-BINDING PROTEIN FROM GOOSE (ANSER ANSER) EGG-YOLK

The riboflavin-binding protein, purified from goose egg yolk, is signi ficantly larger than those previously isolated from other avian specie s. This is, in part, due to a larger polypeptide chain, but mainly to a much higher carbohydrate content, principally glucose and sialic aci d. Approximately one-third of the glucose residues can be released by incubation with a mixture of exo-1-4-alpha- and exo-1,4-beta-D-glucosi dases. The amino acid composition is similar to that of other riboflav in-binding proteins, but the peptide maps are distinct from those of d omestic fowl. The goose egg yolk protein has a much higher proportion of beta-sheet than either domestic fowl or quail riboflavin-binding pr otein.