title: Isolation of corticotropin-beta-lipotropin common precursor from ovine pituitary glands.
abstract: Ovine corticotropin-beta-lipotropin common precursor was purified to homogeneity from commercial frozen ovine pituitary glands. A crude preparation was obtained following a procedure published elsewhere (Lee, T.H. and Lee, M.S. (1977) Biochemistry 16, 2824-2829) and was purified by gel filtration on Sephadex G-200 in the presence of 0.5% SDS and 0.1% 2-mercaptoethanol, and under an atmosphere of nitrogen. The gel filtration was repeated once. The partially purified preparation obtained from the second Sephadex G-200 gel filtration was further fractionated by preparative SDS-acrylamide gel electrophoresis, using immunoprecipitated and electrophoretically purified [125I]corticotropin-beta-lipotropin common precursor as a marker. The preparation was judged homogeneous by the appearance of a single protein band in analytical SDS-acrylamide gel electrophoresis, which exhibited both corticotropin and beta-lipotropin immunoreactivities, and a single symmetrical peak in high-pressure liquid chromatography on a reverse phase C18 column. The isolated ovine corticotropin-beta-lipotropin common precursor possessed specific activities of 116 micrograms of immunoreactive corticotropin and 210 micrograms of immunoreactive beta-lipotropin per mg of protein, equivalent to 89 and 62% of theoretical values, respectively. The amino acid composition of the homogeneous preparation was determined.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D010902:Pituitary Gland / Q000032:analysis*; D010908:Pituitary Hormones, Anterior / Q000302:isolation & purification*; D011333:Pro-Opiomelanocortin; D011498:Protein Precursors / Q000302:isolation & purification*; D012756:Sheep
chemical_list: D000596:Amino Acids; D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; D011333:Pro-Opiomelanocortin