Isolation and characterization of two forms of Xenopus prolactin.
Two forms of highly purified prolactin (PRL) were obtained from pituitary glands of Xenopus laevis by extraction of acetone-dried powder with acid acetone and high-performance liquid chromatography on anion exchange, gel filtration, and reverse-phase columns. Purification was monitored by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis employing antiserum against bullfrog PRL. The Xenopus prolactins (xPRL-I and xPRL-II) thus obtained were shown to have similar molecular weights of 23,000 as determined by SDS-PAGE. The isoelectric points of xPRL-I and xPRL-II determined by isoelectric focusing were 5.6 and 5.3, respectively. Both hormones blocked T4-induced shrinkage of Xenopus tadpole tail fin in vitro. The amino acid compositions of the xPRLs resembled that of bullfrog PRL. The partial amino acid sequences of xPRL-I and of xPRL-II showed 78 and 68% homology with the comparable portion of the sequence of bullfrog PRL, respectively. Homology between xPRL-I and xPRL-II was 90%.
Yamashita
K
K
Department of Biology, School of Education, Waseda University, Tokyo, Japan.
Matsuda
K
K
Hayashi
H
H
Hanaoka
Y
Y
Tanaka
S
S
Yamamoto
K
K
Kikuyama
S
S
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D015153:Blotting, Western; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D007814:Larva; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry*; D011388:Prolactin / Q000032:analysis / Q000302:isolation & purification*; D013974:Thyroxine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014982:Xenopus laevis
D000596:Amino Acids; D011388:Prolactin; D013974:Thyroxine