Proteolysis of insoluble porcine gastric mucus.

Gastric mucus of the pig (Sus scrofa L.) has been separated into two distinct components in guanidine:urea:phosphate. The insoluble gelatinous phase has been solubilized by reduction in bicarbonate buffer. Gel filtration chromatography suggests the presence of a high molecular weight (1.92 X 10(6] and a low molecular weight (6.25 X 10(5] mucoprotein. Proteolytic digestion with trypsin, papain and pronase yielded glycopeptides whose molecular weights ranged from 2.6 X 10(5) to 6.25 X 10(5). Amino acid analysis of each mucoprotein fragment was determined. Notable differences when compared to soluble mucus glycoproteins lie in the conservation of those amino acids likely to be involved in the O-glycosyl linkage.