ISOLATION AND STRUCTURAL CHARACTERIZATION OF 2 NOVEL PEPTIDES DERIVEDFROM PROOPIOMELANOCORTIN IN THE PITUITARY OF THE RAINBOW-TROUT

The trout possesses two POMC genes as a result of duplication of its g enome some 25-100 million years ago, One of the POMC molecules exhibit s a unique C-terminal extension of 25 amino acid residues which is not found in any other POMC characterized so far, In order to isolate pos sible novel peptides derived from trout POMC-A, we have raised antibod ies against two synthetic epitopes derived from the C-terminal region of the precursor, Two native decapeptides were isolated in pure form f rom an extract of trout pituitary. The primary structures of these pep tides were established as Glu-Gln-Trp-Gly-Arg-Glu-Glu-Gly-Glu-Glu and Ala-Leu-Gly-Glu-Arg-Lys-Tyr-His-Phe-GLn-NH2. The structure of the trou t POMC-A cDNA reveals that both peptides are flanked by pairs of basic amino acids or a glycine residue, indicating that they can actually b e generated during post-translational processing of POMC-A. (C) 1997 A cademic Press.