Isolation of a proform of porcine secretin by ion-exchange and reversed-phase high-performance liquid chromatography.

A polypeptide with secretin-like bioactivity has been isolated from upper small intestinal porcine tissue by ion-exchange and reversed-phase high-performance liquid chromatography (HPLC). The purification was followed by determination of biological activity. Its elution position in the ion-exchange HPLC indicated that it was less basic than secretin. Amino acid analysis showed that it contained an additional glycine residue as compared to secretin. Digestions by trypsin and subtilisin established that the polypeptide was a variant form of secretin in which the previously known secretin is extended C-terminally by a glycine residue.