SELH is a selenoprotein, which contains a selenocysteine (Sec) residue at its active site. The selenocysteine is encoded by the UGA codon that normally signals translation termination. The 3' UTR of selenoprotein genes have a common stem-loop structure, the sec insertion sequence (SECIS), that is necessary for the recognition of UGA as a Sec codon rather than as a stop signal. The exact function of this gene is not known, however, selenoproteins are thought to be responsible for most biomedical effects of dietary selenium. Recombinant human SELH protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.