Structural studies on dissociated porcine gastric mucus gel.

Reduction of the insoluble porcine mucus gel with dithiothreitol, followed by molecular sieve chromatography, resulted in the recovery of the two fragments of molecular size 2.54 X 10(6) and 1.75 X 10(6). Both gastric mucus glycoproteins have been cleaved by pronase, papain or trypsin into fragments whose molecular sizes range from 5.60 X 10(5) to 1.87 X 10(6) daltons. On reduction, the enzyme-treated fragments were further dissociated into smaller fragments which have been characterized by SDS-PAGE. The evidence indicates that the pol: neric structure of gastric mucus differs from that of mucus of varying origins, in particular with respect to the size and number of component subunits per native molecule.