Retinol-binding protein ELISA kits are assays designed to measure levels of the protein retinol-binding protein in biological samples, such as plasma, serum, culture extracts, and cell lysates. Retinol-binding proteins are proteins that specifically bind with retinol. In plasma, retinol-binding protein exhibits alpha-1 mobility on electrophoresis with a molecular weight of approximately 21 kDa, while the retinol-protein complex circulates in the form of a larger protein-protein complex (80-90 kDa) with prealbumin. Tissue-specific retinol-binding protein, found in tissues, has a molecular weight of 14 kDa and carries retinol as a noncovalently bound ligand. Click on the ELISA products below and visit the supplier for more information, including assay sensitivity and target specificity.