Porcine gastric TFF2 is a mucus constituent and differs from pancreatic TFF2.

BACKGROUND/AIMS TFF2 is a secretory peptide (106 amino acid residues) of the gastric mucosa, the porcine exocrine pancreas as well as immune cells and the CNS. It was the aim of this study to compare gastric and pancreatic TFF2. METHODS TFF2 was purified from the porcine stomach and pancreas, respectively, by size-exclusion and anion-exchange chromatography and then analyzed by Western blots as well as mass spectrometry. RESULTS Gastric and pancreatic TFF2 differed markedly, i.e. gastric TFF2 was exclusively associated with the high molecular mass mucus fraction, whereas pancreatic TFF2 appeared as a low molecular mass product. Unexpectedly, the latter predominantly formed a non-covalently linked homodimer resistant to boiling SDS. In contrast, gastric TFF2 is an integral mucus constituent predominantly binding to the mucin MUC6 in a non-covalent fashion. CONCLUSION The non-covalent interaction of TFF2 with the mucin MUC6 is typical of a "link peptide" which is perfectly suited to assemble and stabilize the laminated structure of gastric mucus and to modulate its rheological properties.