The goal of this study was to provide a reasonable assessment of how probe substrate selection may impact the results of in vitro aldehyde oxidase (AO) inhibition experiments. Here, we used a previously studied set of seven known AO inhibitors to probe the inhibition profile of a pharmacologically relevant substrate N-[(2dimethylamino)ethyl]acridine-4-carboxamide (DACA). DACA oxidation in human...