On the stoichiometry of the interaction between prealbumin and retinol-binding protein.
The stoichiometry of the interaction between prealbumin and retinol-binding protein was investigated. Gel chromatography analyses of prealbumin on columns equilibrated with retinol-binding protein (RBP)-containing buffers and fluorescence polarization analyses of RBP in the presence of various concentrations of prealbumin demonstrated that 3 molecules of RBP could simultaneously bind to prealbumin. Each RBP molecule seemed to interact with prealbumin with an apparent association constant of about 7.8 X 10(6) M-1. Fab fragments of anti-iudiotypic antibodies raised against anti-RBP antibodies reaced specifically with the RBP-binding sites on prealbumin. Two anti-idiotypic Fab fragments could simultaneously interact with prealbumin. These data strongly suggest that prealbumin exhibits at least two RBP-binding sites.
D001665:Binding Sites; D001667:Binding, Competitive; D006801:Humans; D007118:Immunoassay; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D007700:Kinetics; D011228:Prealbumin; D011485:Protein Binding; D011507:Proteinuria; D012177:Retinol-Binding Proteins; D012709:Serum Albumin; D013050:Spectrometry, Fluorescence
D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D011228:Prealbumin; D012177:Retinol-Binding Proteins; D012709:Serum Albumin