Retinol and retinoic acid-binding proteins in bovine retina: Aspects of binding specificity

Bovine serum contains no apoprotein of low molecular weight with the capacity to bind either [ 3H]retinol or [ 3H]retinoic acid, and the intact retinol-binding protein complex of bovine serum is resistant to exchange of ligand. Acetone-extracted serum bound both ligands, but no evidence of the presence of any low molecular weight protein showing preferential binding of retinoic acid could be found. Bovine retina contains low molecular weight proteins capable of binding and exchanging [ 3H]retinol and [ 3H]retinoic acid, one displaying specificity toward retinol and another showing greater specificity toward retinoic acid.