title: The phylogeny of Met-enkephalin and Leu-enkephalin: studies on the holostean fish Lepisosteus platyrhincus and the Australian lungfish, Neoceratodus forsteri.
abstract: Acid extracts of the brain of the holostean fish Lepisosteus platyrhincus and the forebrain of the dipnoan fish Neoceratodus forsteri were separately fractionated by Sephadex G-50 column chromatography. For both species, Met-enkephalin-related immunoreactivity was detected coeluting with the total volume internal standard. Higher-molecular-weight Met-enkephalin-containing immunoreactive peaks were not detected in these chromatographs. Furthermore, immunoreactive forms with antigenic determinants identical to mammalian dynorphin A(1-17), dynorphin A(1-8), alpha-neo-endorphin, or dynorphin B(1-13) were not detected in either species. Reverse-phase HPLC analysis of enkephalin-sized immunoreactive material indicated the presence of authentic Met-enkephalin and Leu-enkephalin in the extracts of both species. In the brain of L. platyrhincus the molar ratio of Met-enkephalin to Leu-enkephalin was approximately 3:1, whereas, the molar ratio of these enkephalins in the forebrain of N. forsteri was approximately 5:1 [corrected]. C-terminally extended forms of Met-enkephalin were also detected in the extracts of both species. These results suggest that the ancestral proenkephalin gene of both actinopterygian and sarcopterygian fish contained both the Met-enkephalin and Leu-enkephalin sequences.
authors.affiliation: University of Denver, Department of Biological Sciences, Colorado 80208.
authors.forename: L K
authors.initials: LK
authors.lastname: McDonald
authors.forename: J M
authors.initials: JM
authors.lastname: Joss
authors.forename: R M
authors.initials: RM
authors.lastname: Dores
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D004743:Enkephalin, Leucine / Q000235:genetics*; D004744:Enkephalin, Methionine / Q000235:genetics*; D004745:Enkephalins / Q000032:analysis; D005260:Female; D005399:Fishes / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011498:Protein Precursors / Q000032:analysis; D011863:Radioimmunoassay
chemical_list: D004745:Enkephalins; D011498:Protein Precursors; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C033660:preproenkephalin