In vitro biosynthesis and processing of immunologically identified methionine-enkephalin precursor protein.
The biosynthesis and initial processing of the methionine-enkephalin precursor preproenkephalin A were examined by cell-free translation of mRNA from brain and adrenal medulla. A novel antiserum raised against Met-enkephalin-Arg6-Phe7 was shown to react with bovine adrenal medulla fractions (apparent Mr 34,000) containing proenkephalin A. Affinity-purified antibodies from this antiserum were used to immunoprecipitate cell-free translated [35S]Met-enkephalin-containing protein. A protein of apparent Mr 30,000 +/- 500 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was the only Met-enkephalin precursor consistently synthesized by translation of mRNA from bovine or guinea pig striatum, rat brain, or bovine adrenal medulla. The presence of [35S]Met-enkephalin sequences in this protein was confirmed by high pressure liquid chromatography of trypsin/carboxypeptidase B digests. Dog pancreas endoplasmic reticulum membranes converted the Mr 30,000 protein to an immunoreactive protein of apparent Mr 28,500 that lacked significant core glycosylation. These results suggest that 1) a protein similar or identical to bovine adrenal medullary preproenkephalin A is the major Met-enkephalin precursor synthesized in brain as well as adrenal medulla, and 2) preproenkephalin A is converted to a protein resembling proenkephalin A, presumably by removal of a signal peptide.
D000818:Animals; D000918:Antibody Specificity; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000276:immunology; D006168:Guinea Pigs; D007106:Immune Sera; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis*; D011817:Rabbits
D007106:Immune Sera; D011498:Protein Precursors; C026402:pro-Met-enkephalin; D004744:Enkephalin, Methionine; C027511:enkephalin-Met, Arg(6)-Phe(7)-