Dissociation of the bovine serum retinol-binding protein-transthyretin complex and purification of the two interacting proteins

1. Retinol-binding protein is present in bovine serum essentially in the complexed form, bound to transthyretin, as in the case of the other mammalian retinol-binding proteins. 2. Bovine retinol-binding protein-transthyretin complex has the distinctive property of undergoing dissociation in the course of the DEAE-Sephadex chromatography of serum proteins. Therefore, the isolation of uncomplexed retinol-binding protein upon chromatography on this resin cannot represent evidence for lack of binding between it and TTR in bovine plasma, in contrast with previously reported conclusions (Heller J. (1975) J. biol. Chem. 250, (6549-6554). 3. Purified bovine retinol-binding protein and transthyretin can reconstitute a tight complex.