文章基本信息

标题：SOME CHARACTERISTICS OF CYTOSOL BINDING PROTEIN FOR 1α, 25-DIHYDROXYCHOLECALCIFEROL AND 25-HYDROXYCHOLECALCIFEROL IN RAT INTESTINAL MUCOSA
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作者：Fumio SHIMURA ; Sachiko MORIUCHI ; Norimasa HOSOYA 等
期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1977
卷号：23
期号：3
页码：187-200
DOI：10.3177/jnsv.23.187
出版社：Center for Academic Publications Japan
摘要：Cytosol binding protein for 1α, 25-(OH)₂D₃ and 25-OHD₃ was demonstrated in rat intestinal mucosa using sucrose density gradient ultracentrifugation analysis, Sephadex G-200 column chromatography and polyacrylamide disc gel electrophoresis. The binding protein has a sedimentation constant of 5-6S, a molecular weight of 100, 000-120, 000 daltons and a mobility in electrophoresis of R_f 0.42. Further analysis of binding behavior by DEAE-cellulose filter assays revealed that the binding protein had a higher affinity for 25-OHD₃ than for 1α, 25-(OH)₂D₃, and that 1α, 25-(OH)₂D₃ competed with 25-OHD₃ for the same binding site on the protein. The apparent dissociation constant for 1α, 25-(OH)₂D₃ and 25-OHD₃ was 9.2×10^-9 M and 1.5×10^-9 M, respectively. The binding capacity was 3.1 pmoles/mg protein for both 1α, 25-(OH)₂D₃ and 25-OHD₃. The order of binding affinity was 25-OHD₃>1α, 25-(OH)₂D₃>>D₃=1α-OHD₃