title: Purification and characterization of a non-vitellogenin, estrogen-induced plasma protein from the American bullfrog Rana catesbeiana.
abstract: A non-vitellogenin, estrogen-induced protein has been detected for the first time in the plasma of male Rana catesbeiana. A greater than 90% purification of this plasma protein was achieved by salt fractionation with Mg(II) followed by ion-exchange chromatography on DEAE- and CM-cellulose. Immunoelectrophoretic analysis with various antisera showed no immunological cross-reactivity between this protein and vitellogenin. The molecular mass of the purified protein was determined to be 116 000 daltons by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and 105 000 daltons by analytical ultracentrifugation. Sedimentation studies indicate the protein is a nonaggregating spherical monomer with a sedimentation coefficient of 7.5 S. Amino acid analysis demonstrated a composition different from that of vitellogenin and lipovitellin A. Limited proteolysis with trypsin, chymotrypsin, and Bacillus subtilis protease revealed no common peptides on SDS-polyacrylamide gels. Phosphate analysis indicated that, on a molar basis, the non-vitellogen, estrogen-induced protein had less than or equal to 3% of the phosphate found in vitellogenin. Further studies of the structure, function, and metabolism of this protein may reveal information relating to the hormonal control of vitellogenesis.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004958:Estradiol / Q000494:pharmacology*; D007122:Immunoelectrophoresis; D008297:Male; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011892:Rana catesbeiana; D011894:Rana pipiens; D013045:Species Specificity; D014819:Vitellogenins / Q000302:isolation & purification; D014981:Xenopus
chemical_list: D001798:Blood Proteins; D010446:Peptide Fragments; D014819:Vitellogenins; D004958:Estradiol