Targeting of the highly conserved threonine 302 residue of cytochromes P450 2B family during mechanism-based inactivation by aryl acetylenes

► Thr302 is susceptible to mechanism-based inactivation by aryl acetylenes. ► Thr302 forms an ester adduct with the reactive intermediate of tBPA, leading to the inactivation of P450 2Bs. ► tBPA is a potent mechanism-based inactivator of P450 2Bs because of its unique binding mode in the active site of P450 2Bs. ► This unique binding mode of tBPA in CYP2Bs may serve as a basis for designing more specific inhibitors for P450s.