RBP7, also known as CRBP4, belongs to a superfamily of small cytoplasmic proteins which interact with hydrophobic ligands. RBP7 is cytoplasmic protein that, like CRBP I and CRBP II, form β-barrel structures and participates in the intracellular transport of retinol. RBP7 is a recently identified cellular retinol carrier, expressed in the kidney, heart and transverse colon in humans. Recombinant human RBP7 protein, fused to His-tag at Nterminus, was expressed in E.coli and purified by using conventional chromatography techniques.