UbcH5a, also known as UBE2D1, is a member of the ubiquitin E2 conjugating enzyme family, essential components of the ubiquitin cascade.
The selectivity of the ubiquitin cascade for a particular substrate protein relies on the interaction between the E2 conjugating enzyme (of which a cell contains relatively few) and an ubiquitin E3 ligase, of which over 600 have been identified to date. The specific E2-E3 pair required for ubiquitination of a particular substrate protein in vivo may also control the type of ubiquitin modification (mono-, multi-, poly-ubiquitin), the exact substrate lysine residue(s) to be modified and, in the case of polyubiquitination, the chain length and lysine linkage type.
UbcH5a has been shown to interact in vivo with the breast cancer associated DNA damage response enzymes BARD1 and BRCA1 and to be involved in the E6AP mediated ubiquitination of p53. In vitro it acts as a promiscuous E2 and is able to interact with a range of different E3 enzymes and participate in polyubiquitin chain synthesis.
Recombinant human UbcH5a protein expressed with a N-terminal His-tag. Protein has utility in ubiquitination reactions, polyubiquitin chain synthesis, identification of substrate specific E2-E3 pairs and determination of E2 polyubiquitin linkage specificity.