Isolation and chemical characterization of glicentin C-terminal hexapeptide in porcine pancreas.
Using a radioimmunoassay specific for porcine glicentin C-terminal hexapeptide, we isolated a peptide from porcine pancreas and characterized it as the C-terminal 64-69 sequence of glicentin: H-Asn-Lys-Asn-Asn-Ile-Ala-OH. The purification steps included gel filtration, ion-exchange chromatography and HPLC. In each step, the recovery of the desired peptide, radioimmunologically estimated from the respective elution profile, was 71.4-91.7%. The final yield of the hexapeptide was 22 micrograms (4.3%) from 800 g pancreas. The pancreatic content of this peptide was estimated to be approximately equimolar to that of pancreatic glucagon. No hexapeptide-like component was detected in porcine intestinal extracts. The data confirmed that the processing of pancreatic proglucagon liberates the C-terminal hexapeptide of the intramolecular glicentin sequence in a tissue-specific manner during the production of glucagon.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005934:Glucagon / Q000032:analysis*; D010179:Pancreas / Q000032:analysis*; D052336:Proglucagon; D011498:Protein Precursors / Q000032:analysis*; D011863:Radioimmunoassay; D013552:Swine
D000596:Amino Acids; D011498:Protein Precursors; D052336:Proglucagon; D005934:Glucagon