Ubiquitin-conjugating enzyme E2 A isoform 1, also known as UBE2A is a member of the E2 ubiquitin-conjugating enzyme family. This enzyme is required for post-replicative DNA damage repair. Multiple alternatively spliced transcript variants have been found for this gene and they encode distinct isoforms. Recombinant human UBE2A, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.