Interaction between Prealbumin and Retinol‐Binding Protein Studied by Affinity Chromatography, Gel Filtration and Two‐Phase Partition

Abstract

The interaction between prealbumin and apo or holo retinol‐binding proteins has been studied by affinity chromatography, gel filtration and two‐phase partition. At physiological ionic strength apo and holo retinol‐binding protein form 1:1 molar complexes with prealbumin. Mean dissociation constants for the prealbumin complex with apo retinol‐binding protein and holo retinol‐binding protein with all‐trans retinol, retinoic acid, retinal and retinyl acetate were calculated from the partition data as 0.33 ± 0.11 × 10‐6 M and 0.075 ± 0.015 × 10‐6 M respectively (mean ± S.E.M.). The difference was statistically significant. Quantitative data on the amount of retinol, retinol‐binding protein and prealbumin in plasma and urine were in good agreement with the ratio of the dissociation constants for the complexes of apo and holo retinol‐binding proteins with prealbumin as determined in the partition experiment. The magnitude of the dissociation constants was compatible with previously published data on the turnover of retinol‐binding protein. Copyright © 1979, Wiley Blackwell. All rights reserved