The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes, or E1s, ubiquitin-conjugating enzymes, or E2s, and ubiquitin-protein ligases, or E3s. UBE2E1 is a member of the E2 ubiquitin-conjugating enzyme family. Two alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. Recombinant human UBE2E1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.