StAR-related lipid transfer protein 5, also known as STARD5, belongs to the STARD family of proteins is comprised of fifteen different members. All members contain the characteristic START domain and are believed to play key roles in the metabolism and transport of lipids. The STARD proteins are grouped into six subfamilies based on their START domain sequences. STARD5 constitute one subfamily, sharing approximately 30% amino acid identity with each other. STARD5 is not sterol-regulated but can be induced by endomplasmic reticulum (ER) stress. Due to its exclusive tissue expression and its interaction with sterols, StARD6 may function in reproduction and germ cell maturation. Recombinant human STARD5 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.