The attachment of carbohydrate in ovomucoid

Very little information has been available until recently about the nature of the bonds between the protein and carbohydrate moieties in complexes containing them in covalent linkage It appears that aspartic acid is directly linked to the carbohydrate in hen-egg albumin (Cunningham, Nuenke & Nuenke, 1957; Jevons, 1958; Johansen, Marshall & Neuberger, 1958, 1961) and in human y-globulin Gottschalk & With chondroitin sulphate (where the carbohydrate is of a different type, containing uronic acid and sulphate but not neutral sugar), the complex with protein extract- able from pig trachea, after digestion with papain, retains no amino acid except serine in stoicheiometrically significant amounts, and bonds between this and acidic groups in the carbohydrate were postulated (Muir, 1958).