title: Met5-enkephalin-Arg6-Gly7-Leu8 immunoreactivity in the human gut.
abstract: The presence of the proenkephalin A-derived peptide Met5-enkephalin-Arg6-Gly7-Leu8 was demonstrated throughout the human gastrointestinal tract. Highest concentrations of Met5-enkephalin-Arg6-Gly7-Leu8, as assessed by radioimmunoassay, were measured in the separated muscularis externa, while lower levels were found in the submucosa and only small amounts in the mucosa. The results are consistent with a neuronal location of this peptide in the human gut. Over 65% of total immunoreactivity coeluted with the authentic peptide in both molecular exclusion chromatography and HPLC, while most of the remainder activity eluted earlier on gel filtration. The latter material probably represents N-terminally extended Met5-enkephalin-Arg6-Gly7-Leu8. Taken together with previous studies, our results appear to indicate that there are important species differences in post-translational processing of proenkephalin A in gut nerves.
mesh_terms: D003106:Colon / Q000032:analysis; D003429:Cross Reactions; D004064:Digestive System / Q000032:analysis / Q000473:pathology; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000032:analysis; D005753:Gastric Mucosa / Q000032:analysis; D005770:Gastrointestinal Neoplasms / Q000473:pathology / Q000601:surgery; D006801:Humans; D007106:Immune Sera; D007413:Intestinal Mucosa / Q000032:analysis; D007421:Intestine, Small / Q000032:analysis; D011863:Radioimmunoassay; D012007:Rectum / Q000032:analysis; D013270:Stomach / Q000032:analysis
chemical_list: D007106:Immune Sera; D004744:Enkephalin, Methionine; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-