UBE2S, also known as ubiquitin-conjugating enzyme E2S, is a member of the ubiquitin-conjugating enzyme family. This protein is able to form a thiol ester linkage with ubiquitin in an ubiquitin activating enzyme-dependent manner, a characteristic property of ubiquitin carrier proteins. It catalyzes the covalent attachment of ubiquitin to other proteins. Recombinant UBE2S protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.