APP and obesity due to melanocortin 4 receptor deficiency: Previous applications of RP‐ABPP have demonstrated electrophilic activity on numerous disease‐associated proteins [e.g., Kelch‐like ECH‐associated protein 1 (KEAP1) in cancer, amyloid precursor protein (APP) in Alzheimer's disease, fat mass and obesity‐associated protein (FTO) in obesity, etc.] that were not previously known to harbor such reactivity (Matthews et al., 2017).