UbcH2, also known as UBE2H, 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.