Accepts the ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [E2 ubiquitin-conjugating enzyme]-L-cysteine = [E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine. Protein modification; protein ubiquitination. Expressed in all tissues examined. Lower levels found in leaves. Up-regulated by syringolin, a cell death-inducing chemical, but not induced by heat shock. Belongs to the ubiquitin-conjugating enzyme family. Truncated C-terminus. Truncated C-terminus.