Isolation and characterization of cholecystokinin-58 (CCK-58) from porcine brain

A 58-residue peptide has been isolated from extracts of porcine brain and shown to be an N-terminally extended cholecystokinin (CCK). The amino acid sequence of this peptide is: Ala-Val-Gln-Lys-Val-Asp-Gly-Glu-Ser-Arg-Ala-His-Leu-Gly-Ala-Leu-Leu-Ala- Arg-Tyr- Ile-Gln-Gln-Ala-Arg-Lys-Ala-Pro-Ser-Gly-Arg-Val-Ser-Met-Ile-Lys-Asn-Leu- Gln-Ser- Leu-Asp-Pro-Ser-His-Arg-Ile-Ser-Asp-Arg-Asp-Tyr(SO3)-Met-Gly-Trp-Met-Asp -Phe-NH2. The peptide was found to induce contraction of the guinea-pig gallbladder, but the pattern of this action seemed to differ from those of CCK-8 and CCK-33.