[Chemical composition of casein glycomacropeptide components].

Alteration in pH and addition of urea (final concentration 3 M) did not affect the electrophoretic and chromatographic separation of glycomacropeptide. At the same time, urea (5 M) distinctly increased an amount of beta-component in separation by free electrophoresis. Sedimentation constant SO2OW and molecular weight of glycomacropeptide were equal to 1.35 S and 13000, respectively. Both fractions of glycomacropeptide had similar amino acid composition and contained phosphorus (0.4%). The variations were observed in the carbohydrate components of the molecules. The heavy component contained 5-fold higher concentration of sialic acids (9.7-9.6%), 2-fold higher concentration of galactose (13%) and acetyl galactosamine (5.0-4.0%) as compared with the beta-component (3.1-0.9%, 7.5% and 2.5%, respectively). These alterations in carbohydrate component of glycomacropeptide were suggested to affect the polymeric conformation of the molecule.