Enzyme profiling is the systematic characterization of enzyme activities across proteins, samples, or biological conditions. Activity-based profiling uses chemical probes that react with accessible catalytic machinery to record active members of particular enzyme classes ^[1]. Competition between a probe and an inhibitor can reveal which enzymes are engaged by the compound within a biological sample ^[2]. Probe recognition and reactivity determine the subset of the enzyme population that is labeled, while an attached reporter or enrichment handle permits detection and identification of the labeled proteins ^[3]. The resulting pattern combines information about protein identity, accessible activity, and experimental conditions. Comparing profiles across samples reveals changes in the measured enzyme population, provided that probe exposure, sample handling, and detection are sufficiently comparable ^[4].