Proteins were considered to be iodoacetamide-reactive if they were directly modified by the iodoacetamide probe, and were considered chloroacetamide-reactive if any of the 158 tested chloroacetamides could outcompete iodoacetamide reactivity by a factor of 4-fold (Figure ). For each chloroacetanilide herbicide, there is no enrichment of more reported reactive proteins at higher Hsp40 affinity follow herbicide treatment. About 12% of our identified proteins have reported chloroacetamide reactivity, independent of chloroacetanilide-induced destabilization. This finding strongly agrees with a central conclusion from the prior work: chloroacetamide reactivity is sparse, with most molecules showing substantial specificity to individual proteins. In keeping with the greater reactivity of iodoacetamides, about 70% of our identified proteins have reported iodoacetamide reactivity, again independent of chloroacetanilide-induced destabilization. This finding is more surprising, but could reflect that Hsp40 affinity is not the same as reactivity; adduct formation can have different effects on protein stability for different proteins. Indeed, there is no correlation between the promiscuity of a protein for chloroacetamide modification and it's destabilization by any of the three chloroacetanilides that we profiled (Figure ). Nevertheless, our most affected proteins are iodoacetamide reactive, consistent with the primary mechanism of protein destabilization due to cellular chloroacetanilide exposure being mediated through direct conjugation at reactive cysteines (Figure ).