Isolation and primary structure of a novel chromogranin A-derived peptide, WE-14, from a human midgut carcinoid tumour.

The primary structure of a novel human chromogranin A-derived tetradecapeptide, WE-14, possessing N-terminal tryptophanyl (W) and C-terminal glutamyl (E) residues was isolated from a hepatic metastasis of an human ileal carcinoid tumour. Human and bovine WE-14 are structurally identical, while rat, mouse and porcine analogues exhibit 93% homology. WE-14 is flanked by paired basic residues (KR) in all known chromogranin A sequences.