Action of Alkali on Bovine and Ovine Submaxillary Mucins

Treatment of solutions of bovine and ovine submaxillary mucins with alkaline sodium borohydride at 45° for 10 hours converted essentially all of the carbohydrate chains to dialyzable materials. However, 17 to 25% of the hexosamine was not reduced to the hexosaminitol and probably was present as a glycopeptide. The Hestrin hydroxylamine method for the determination of esters was applied to bovine, ovine, and porcine submaxillary mucins and to ovalbumin and serum α-glycoprotein. The only materials having ester content were preparations of bovine submaxillary mucin. The characteristics of the acyl function corresponded solely to that of the O-acetyl groups of the constituent sialic acids. After treatment of the bovine mucin with hydroxylamine, the constituent sialic acid could be almost completely removed by neuraminidase.