Two Adrenal Opioid Polypeptides: Proposed Intermediates in the Processing of Proenkephalin

• Published in: Proceedings of the National Academy of Sciences - PNAS 1981-03, Vol.78 (3), p.1962-1966
• Main Authors: Stern, Alvin S., Jones, Barry N., Shively, John E., Stein, Stanley, Udenfriend, Sidney
• Format: Article
• Language: English
• Subjects: Adrenal Medulla - metabolism; Amino Acid Sequence; Amino acids; Animals; Biochemical pathways; Bromides; Cattle; Chromaffin cells; Chromaffin Granules - metabolism; Chromaffin System - metabolism; Endorphins - biosynthesis; Enkephalins - biosynthesis; Enkephalins - isolation & purification; Hydrolysis; Molecules; Neurobiology; Opioid analgesics; Peptide Fragments - analysis; Protein Precursors - biosynthesis; Protein Precursors - isolation & purification; Sequence analysis; Trypsin; Ungulates
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.78.3.1962

Two enkephalin-containing polypeptides of 3600 and 4900 daltons have been isolated from extracts of bovine adrenal medulla, purified to homogeneity, and analyzed by a combination of automated Edman degradation and enzymatic time course hydrolysis. The 4900-dalton polypeptide contains two copies of enkephalin, one an internal [Met] enkephalin sequence, the other a [Leu]enkephalin sequence at the carboxyl terminus. Sequence analysis of the 3600-dalton polypeptide has not been completed, but the polypeptide has been shown to contain a single [Met]enkephalin sequence followed by an -Arg-Phe linkage that forms the carboxyl terminus of the molecule. On the basis of these and other findings, we propose that the above enkephalin-containing polypeptides are intermediates in the biosynthesis of the enkephalins and that they are generated by posttranslational processing from a large multivalent enkephalin precursor molecule, proenkephalin. The term ``multivalent'' is used to indicate a polypeptide with many identical functional sequences.