IDENTIFICATION OF A 7B2-DERIVED TRIDECAPEPTIDE FROM BOVINE ADRENAL-MEDULLA CHROMAFFIN VESICLES

1. A novel tridecapeptide was isolated from extracts of bovine adrenal medulla chromaffin vesicles and the primary structure determined to b e SVPHFSDEDKDPE.2. This peptide is identical to the C termini of human and porcine 7B2 and is highly homologous to the same region of the mo use and Xenopus lavis protein. 3. In all these species the homologous peptide is preceded by a pair of lysine residues, a potential proteoly tic processing site. 4. Ser6 is part of a well-conserved casein kinase II consensus phosphorylation sequence. Evidence for phosphorylation o f this residue was obtained during Edman sequencing. 5. Thus, this nov el adrenal medullary probably arises from the posttranslational proces sing of the bovine 7B2 protein.