Binding properties of serum vitamin D transport proteins in vertebrates for 24R, 25-dihydroxycholecalciferol and 24S, 25-dihydroxycholecalciferol in vitro.
1. The affinities of the specific vitamin D plasma transport proteins for 25-hydroxycholecalciferol, 24R, 25-dihydroxycholecalciferol and 24S, 25-dihydroxycholecalciferol were studied in 34 vertebrate species. 2. Fish plasma proteins bound 25-hydroxycholecalciferol, 24R, 25-dihydroxycholecalciferol and 24S, 25-dihydroxycholecalciferol with equal efficiency. 3. Vitamin D transport proteins in birds and a monotreme bound 25-hydroxycholecalciferol more efficiently than 24R, 25-dihydroxycholecalciferol; in one bird the two seco-steroids were bound with equal efficiency. 4. Transport proteins from marsupial and placental mammals bound 24R, 25-dihydroxycholecalciferol more efficiently than 24S, 25-dihydroxycholecalciferol. 5. Twelve mammal transport proteins bound 25-hydroxycholecalciferol and 24R, 25-dihydroxycholecalciferol with equal efficiency, however, in six mammals 25-hydroxycholecalciferol was more efficiently bound.
D015650:24,25-Dihydroxyvitamin D 3; D000818:Animals; D001717:Birds / Q000378:metabolism; D004100:Dihydroxycholecalciferols / Q000097:blood / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism; D008322:Mammals / Q000378:metabolism; D012104:Reptiles / Q000378:metabolism; D013045:Species Specificity; D013237:Stereoisomerism; D013379:Substrate Specificity; D014809:Vitamin D-Binding Protein / Q000097:blood*
D004100:Dihydroxycholecalciferols; D014809:Vitamin D-Binding Protein; D015650:24,25-Dihydroxyvitamin D 3