Proximity Chemistry in Living Systems

Enzyme-and catalyst-generated reactive species have been leveraged in the past decade to covalently label biomolecules within a short range of a defined site or space inside cells or at the cell–cell interface.Due to their high spatial resolution,such proximity labeling strategies have been coupled with various bioanalytical techniques for dissecting dynamic and complex biological processes.Here,we review the development of enzyme-and catalyst-triggered proximity chemistry and their applications to identifying protein interaction networks as well as cell–cell communications in living systems.