Outside of those, the proteins that are most affected by each individual treatment are unique. This selectivity is particularly salient given the high concentrations (1 mM) used for the treatments. The unique profiles of proteins affected by each herbicide is consistent with the high selectivity of protein reactivity with even strongly reactive warheads . We searched for cysteine-chloroacetanilide adducts from each run, finding 32/8637, 40/16029, and 102/15694 modified/total peptides following acetochlor, alachlor, and propachlor treatments respectively. It can be challenging to identify peptide modifications without enriching for the modified sites, as stoichiometry on a per peptide basis for post-translational modifications are often low . Furthermore, when peptide identifications are filtered, the filtration thresholds are set for each search such that the false discovery rate based on a decoy set is <1% of peptides. While that intended threshold is likely reasonably close to the true false discovery rate in the context of the entire proteome , for a modification found on only a small number of modified peptides it introduces a much higher practical risk of misidentification . With these caveats in mind, we include the list of identified chloroacetanilide conjugates in Table . It is also worth noting that we consistently see a DNAJB8 modification at C70. While this is in the DNAJB8 J-domain , which is dispensable for client binding, we cannot rule out the possibility that this modification itself could impact DNAJB8 recognition.