title: Adrenal opioid proteins of 8600 and 12,600 daltons: intermediates in proenkephalin processing.
abstract: [Met]Enkephalin-containing proteins of 8600 and 12,600 daltons have been isolated from acid extracts of bovine adrenal medulla and purified to homogeneity, and their sequences have been determined by a combination of automated Edman degradation, tryptic mapping, and enzymatic time-course hydrolysis. The 8600-dalton protein contains one copy of the [Met]enkephalin sequence at the COOH terminus and the 12,600-dalton protein contains three copies of [Met]enkephalin, of which two are internal and the third is at the COOH terminus. They possess identical NH2-terminal amino acid sequences, suggesting that the 8600-dalton protein is derived from the 12,600-dalton protein by intracellular proteolytic processing. This is supported by results from tryptic maps of both proteins. Furthermore, chemical analysis of the tryptic peptides obtained from the 12,600-dalton protein indicates that it also contains the amino acid sequence that corresponds to a previously characterized enkephalin-containing polypeptide of 3800 daltons (peptide F) [Jones et al. (1980) Arch. Biochem. Biophys. 204, 392-395]. All three polypeptides appear to be intermediates in posttranslational processing of a still larger polyenkephalin precursor molecule, proenkephalin, and part of a biosynthetic pathway leading to smaller enkephalin-containing polypeptides and free enkephalins.
mesh_terms: D000313:Adrenal Medulla / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D004723:Endorphins / Q000096:biosynthesis*; D004745:Enkephalins / Q000096:biosynthesis*; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011498:Protein Precursors / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D004723:Endorphins; D004745:Enkephalins; D010446:Peptide Fragments; D011498:Protein Precursors