Abstract
Cancer cells rely on fatty acid synthase (FASN), a key enzyme for de novo biosynthesis of long chain fatty acids, to sustain their proliferative potential and drive invasion. Unfortunately, conventional FASN assays are technically inadequate for discerning otherwise elusive FASN activity in complex biological milieux, which has hindered progress in the functional study of FASN and development of its inhibitors. Here, we describe a chemical probe with unprecedented selectivity and sensitivity for the labeling of active FASN in living cells, thus demonstrating a new analytical modality for visualizing endogenous FASN activity and exploring opportunities for drug discovery.