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.
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.
Chauvet
J
J
Laboratory of Biological Chemistry, University of Paris VI, France.
Michel
G
G
Rouillé
Y
Y
Chauvet
M T
MT
Acher
R
R
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
D010446:Peptide Fragments; D053497:Corticotropin-Like Intermediate Lobe Peptide; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones