title: Purification and characterization of Mr 43,000 protein similar to Mr 25,000 protein, a substrate for protein Ser/Thr kinases, identified as a part of Xenopus laevis vitellogenin B1.
abstract: Mr 25,000 protein (pp25), a substrate for protein Ser/Thr kinases, was recently shown to consist of a portion of the Xenopus laevis vitellogenin B1 protein. By Western blot analyses using antibodies against pp25, a minor protein band with Mr 43,000 (pp43) was detected in purified preparations of pp25. In this study, pp43 was highly purified through several column chromatography steps and its protein structure was analyzed. The amino acid sequence of the amino-terminal region of pp43 was the same as that of pp25. pp43 contained about two times more phosphates than pp25. These phosphates in pp43 were more resistant to acid phosphatase attack than those of pp25. pp43 was able to bind to pNiXa, a binding protein of pp25. Alpha-chymotryptic digestion generated a common fragment with molecular mass of 23,000 from both pp43 and pp25. These results suggest that pp43 may be a precursor of pp25 generated during processing of vitellogenin B1.
authors.affiliation: Division of Pathological Biochemistry, Department of Biomedical Sciences, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago 683-8503, Japan.
authors.forename: Jin
authors.initials: J
authors.lastname: Xi
authors.forename: Isamu
authors.initials: I
authors.lastname: Sugimoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoshitome
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yasuda
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ogura
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mori
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Li
authors.forename: Susumu
authors.initials: S
authors.lastname: Ito
authors.forename: Eikichi
authors.initials: E
authors.lastname: Hashimoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin / Q000378:metabolism; D003429:Cross Reactions; D005314:Embryonic and Fetal Development; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013379:Substrate Specificity; D014819:Vitellogenins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D000906:Antibodies; D010446:Peptide Fragments; D014819:Vitellogenins; D004958:Estradiol; D017346:Protein Serine-Threonine Kinases; D002918:Chymotrypsin; C117608:alpha-chymotrypsin