抄録
^3H-Vitamin D_2 (^3H-D_2) and ^3H-vitamin D_2-sulfate (^3H-D_2-sulfate) were prepared by Wilzbach method and D_2-sulfate binding proteins from the rabbit intestinal mucosa and plasm were investigated in vitro. The intestinal mucosa proteins reacted with ^3H-D_2 or ^3H-D_2-sulfate, on its gel filtration using Sephadex G-200 column (1.6×70cm), were separated into six protein peaks respectively. Peak 1 equivalent to the void volume was that bound with ^3H-D_2 or ^3H-D_2-sulfate. After pronase treatment of the intestinal mucosa proteins, their binding ability with ^3H-D_2-sulfate were decreased markedly. The disk get electrophoresis of ^3H-D_2-sulfate binding proteins in the peak 1 fraction was also carried out ; all the three bands on the gel stained with amide black showed radioactivity. These results suggest that D_2-sulfate can bind with intestinal mucosa proteins to be absorbed from the intestine. When the rabbit plasm binding proteins with ^3H-D_2-sulfate were separated by gel filtration using Sephadex G-200 column, six protein peaks were observed ; the protein in peak 3 fraction was shown to be that bound with either ^3H-D_2 or ^3H-D_2-sulfate respectively.