# Next-Generation Protein–Ligand Interaction Networks: APEX as a Powerful Technology

## TL;DR

This paper reviews APEX, a powerful peroxidase tool for studying protein interactions in living cells with high precision.

## Contribution

The paper provides a comprehensive overview of APEX's evolution and its novel applications in mapping biological interactions.

## Key findings

- APEX enables high-resolution mapping of protein–ligand interactions in living cells.
- Genetic engineering has enhanced APEX's utility for proteomic and transcriptomic studies.
- Recent innovations in substrates expand APEX's applicability in biological research.

## Abstract

Peroxidases are essential enzymes that catalyze redox reactions, with wide-ranging biological implications. Among these, an enhanced ascorbate peroxidase (APEX) has emerged as a valuable tool for studying intricate intracellular events with spatiotemporal precision, particularly in protein–protein, protein–RNA, and protein–DNA interaction networks in living cells. This review discusses APEX’s structural and functional attributes, its evolution through genetic engineering, and its transformative applications in high-resolution mapping used for proteomic and transcriptomic studies. Furthermore, it highlights recent advancements in substrate innovation and addresses current challenges and future directions in leveraging APEX for cutting-edge biological research.