Binding of bile acids, organic anions, and fatty acids by bovine intestinal Z protein.
Z protein from bovine small intestinal mucosa was purified and its binding affinities for bile acids, organic anions, and fatty acids were compared with those of bovine hepatic Z protein. Purification of Z protein from intestinal and hepatic cytosol was performed by gel filtration, chromatofocusing, and hydroxyapatite chromatography. Both purified proteins had the same molecular weight (Mr 14,000) and eluted from a chromatofocused gel at about pH 10. Binding studies were performed by the competitive displacement of 8-anilinonaphthalene-1-sulfonic acid and by equilibrium dialysis. Binding affinities for bile acids, organic anions, and fatty acids were very similar between intestinal and hepatic Z proteins. Although the real physiologic role of Z protein remains to be further elucidated, these data indicate that intestinal Z protein participates in the mechanism of intracellular bile acid transfer in enterocytes.
Takikawa
H
H
Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan.
Arai
S
S
Yamanaka
M
M
D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D007082:Ileum; D007413:Intestinal Mucosa / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D012964:Sodium / Q000378:metabolism
D001647:Bile Acids and Salts; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D012964:Sodium; D011188:Potassium