Lineweaver-Burk plots and slope/intercept replots of phthalazine oxidation inhibition by eight different inhibitors: DCPIP (A), estradiol (B), menadione (C), ethinyl estradiol (D), domperidone (E), chlorpromazine (F), clozapine (G), and 6-chloroquinazolinone (6-CQ) (H). Each point reflects the average of triplicate determinations.