The overall plan of the proposed project is as follows: To purify cytosol retinol binding proteins (CRBP) and cytosol retinoic acid binding proteins (CRABP) from various sources, including retina, pigment epithelium, testis and liver of rat, dog, cattle, monkey, chicken, frog and turtle. To produce antisera against CRBP and CRABP. To characterize these binding proteins with respect to immunological properties, molecular weight, UV and fluorescence spectra, isoelectric point, electrophoretic behavior, amino acid composition and peptide mapping. To investigate the ligand binding site by determining and binding properties for various vitamin A analogs, by measuring CD spectra for these protein-ligand complexes, and my NMR spectroscopy of the binding proteins coupled with fluorinated ligands (19FNMR). To study the interaction of the double-labeled 14C-protein/3H-ligand complex with nuclei isolated from retina, pigment epithelium and to compare with nuclei from liver. To study the effect of pH on protein-ligand interactions. To obtain the CRBP-retinol complex from retina and pigment epithelium, and to determine the isomeric configuration of the bound retinol in light- and dark-adaptation. To use radioimmunoassay to determine the amount to CRBP in various tissues and in the retina and pigment epithelium during light- and dark-adaptation and in hereditary dystrophic conditions. The overall objective is to understand the molecular structure of retinol binding proteins and their function in the eye, where vitamin A has a special role in the visual process. Deficiencies in such binding proteins or altered binding specificity and affinity for retinol could materially affect the normal functioning of vitamin A in the retina and pigment epithelium of dystrophic eyes.