The Carbohydrates of Some Glycoproteins of Bovine Milk

Abstract

This study was conducted to ascertain the specific carbohydrates associated with the soluble fat globule membrane protein, the Weinstein fraction from rennet treated skimmilk, and the proteose-peptone fraction of Rowland. Using the conventional analysis techniques for protein-bound hexose, hexosamine, fucose, and sialic acid, as outlined by Glick, carbohydrate percentages were determined. To specifically determine carbohydrates, descending chromatograms were run on the acid hydrolysates of the above proteins. Chemical results showed the soluble membrane protein, Weinstein fraction, and proteose peptone, to contain 2.69, 3.46, and 2.90% hexose, respectively, whereas hexosamine was 1.08, 1.10 and 1.15; fucose, 0.71, 0.48, 0.70%; sialic acid, 2.00, 3.60 and 2.00%, respectively. Total carbohydrate for the soluble membrane protein, Weinstein fraction and proteose-peptone was 6.48, 8.64, and 6.75%, respectively. Paper chromatograms showed the presence of fucose, galactosamine (weak), galactose, glucosamine and mannose. Sialic acid appeared on the chromatogram only when milder acid hydrolysis was employed.