ビタミンD_3および25-ヒドロオキシコレカルチフェロールと結合する血漿たんぱく質

抄録

The binding proteins of vitamin D_3 and 25-hydroxycholecalciferol were identified in rat plasma. Five protein peaks (designated as peak 1,2,3,4 and 5 according to the elution order) were observed on the gel filtration of Sephadex G-200 (2.4×65cm). Peak 1,2 and 4 bound with vitamin D_3 and 25-hydroxycholecalciferol. However, peak 2 and 4 bound the considerable amount of vitamin D_3 and peak 4 bound with 25-hydroxycholecalciferol. The properties of these peak fractions were also analyzed with the polyacrylamide gel disc electrophoresis and the sucrose density gradient ultracentrifugation. Vitamin D_3 bound with more than five bands of gel stained with acid blue black 10 B. Four bands of them contained a small amount of carbohydrate and lipid, and a band of them was α-globulin. The α-globulin band associated specifically with 25-hydroxycholecalciferol. The sedimentation constant of vitamin D_3 binding protein was calculated as 14.5 s, 10.5 s, 8.1 s, 6.2 s and 4.3 s, and the 25-hydroxycholecalciferol was as 14.5 s, 10.5 s, 6.8 s and 4.3 s. The sedimentation constant of the protein, to which vitamin D_3 bound specifically, was calculated as about 8.1 s. The protein for 25-hydroxycholecalciferol was 6.8 s.