UBE2D3, also known as ubiquitin-conjugating enzyme E2 D3. 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. This enzyme functions in the ubiquitination of the tumor-suppressor protein p53, which is induced by an E3 ubiquitin-protein ligase. Recombinant human UBE2D3 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.