Ubiquitin 7-amino-4-carbamoylmethylcoumarin as an improved fluorogenic substrate for deubiquitinating enzymes

A new fluorogenic substrate Ub-ACC (ubiquitin C-terminal 7-amino-4-carbamoylmethyl-coumarin) was developed for DUB (deubiquitinating enzyme) activity assays. This substrate can be synthesized with higher efficiency than the classical DUB substrate, Ub-AMC (ubiquitin C-terminal 7-amino-4-methylcoumarin). DUB assays using UCH-L3, OTUD2 and USP30 demonstrated that Ub-ACC shows nearly 2-fold higher sensitivity than Ub-AMC.