RBP2 is an abundant protein present in the small intestinal epithelium. It is thought to participate in the uptake and/or intracellular metabolism of vitamin A. Vitamin A is a fat-soluble vitamin necessary for growth, reproduction, differentiation of epithelial tissues, and vision. RBP2 may also modulate the supply of retinoic acid to the nuclei of endometrial cells during the menstrual cycle. Recombinant human RBP2 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.