... enzymes can beaffected by environmental chemicals, such as drugs orpollutants [18]. More specifically, human NAT1 hasbeen shown to be impaired by oxidants [19–21] and by certain therapeutic ... NAT1 by DS. Dialysis had no significanteffect on NAT1 activity, as also reported by Butcheret al. [30].We then investigated whether the DS-dependentinhibition of NAT1 could be reversed by reducingagents. ... reducingagents. As shown in Table 1, after inhibition by DS,NAT1 activity could not be restored by physiologicalconcentrations of reduced glutathione (GSH) or by high concentrations of the non-physiological...