title: Study of frog (Rana esculenta) proopiomelanocortin processing in the intermediate pituitary. Identification of alpha-melanotropin, beta-melanotropin, Lys-gamma-melanotropin, and corticotropin-like intermediate lobe peptide.
abstract: The proteolytic processing of frog (Rana esculenta) proopiomelanocortin in melanotropic cells of the intermediate pituitary gland has been examined through purification of the mature fragments by reverse-phase high-pressure liquid chromatography and microsequencing of isolated peptides. alpha-Melanotropin, beta-melanotropin, Lys-gamma-melanotropin, corticotropin-like intermediate lobe peptide, and hinge peptide have been isolated and chemically characterized. The results show a high preservation in the processing sites of frog proopiomelanotropin when compared to bovine counterparts. They reveal also a great conservation of the processing enzyme equipment of melanotropic cells in tetrapods species. Identification of Lys-gamma-melanotropin suggests the occurrence of an endopeptidase able to cleave between two basic residues. On the other hand alpha-melanotropin does not appear to be N-acetylated, as previously found in the clawed-toad Xenopus laevis, and this feature might distinguish amphibian from mammalian proopiomelanocortin processing.
authors.affiliation: Laboratory of Biological Chemistry, University of Paris VI, France.
authors.forename: J
authors.initials: J
authors.lastname: Chauvet
authors.forename: G
authors.initials: G
authors.lastname: Michel
authors.forename: Y
authors.initials: Y
authors.lastname: Rouillé
authors.forename: M T
authors.initials: MT
authors.lastname: Chauvet
authors.forename: R
authors.initials: R
authors.lastname: Acher
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000032:analysis*; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D053497:Corticotropin-Like Intermediate Lobe Peptide; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis*; D010902:Pituitary Gland / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011893:Rana esculenta; D014981:Xenopus
chemical_list: D010446:Peptide Fragments; D053497:Corticotropin-Like Intermediate Lobe Peptide; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones