A comparison of the results of sequential hydrazinolysis-nitrosation and alkali-mediated cleavage-nitrosation of the O-linked oligosaccharides of gastric mucus glycoproteins.

Analysis of the oligosaccharides released from pig gastric mucus glycopolypeptides by hydrazinolysis showed that degradation had occurred. Nitrosation of the products followed by reduction gave a mixture that had a low content of 2,5-anhydro-D-talitol, which implied destruction of much of the terminal reducing 2-amino-2-deoxy-D-galactose. Under the conditions of hydrazinolysis, cellobiose was largely unchanged but laminaribiose gave a complex mixture that probably contained glucose hydrazone (13C-n.m.r. data). In order to avoid degradation, the hydrazinolysis-nitrosation sequence should be applied to the reduced oligosaccharides released on cleavage with alkali.