Description
Among ubiquitin-conjugating enzymes, the mammalian ubiquitin conjugating enzyme UbcH1, also known as HIP2, is unique in its ability to catalyze the in vitro synthesis of unanchored Lys48-linked poly-ubiquitin chains from mono- or poly-ubiquitin, E1, and ATP. In addition, UbcH1 can catalyse the cyclization of longer poly-ubiquitin chains, including tetra- and penta-ubiquitin. Recombinant UbcH1 charges and supports ubiquitinylation in vitro. Typical enzyme concentration to support conjugation in vitro is 100nM to 1µM. Recently, HIP2 (or UbcH1) has been shown to bind to the N terminus of Huntington and may play a role in Huntington disease