N-Acetyl-4-benzoquinone Imine (NAPQI) is a toxic cytochrome P450 3A4 and 2E1 metabolite of Acetaminophen. At therapeutic doses of acetaminophen, NAPQI is inactivated by conjugation with glutathione. However, following toxic doses of acetaminophen, available liver reserves of glutathione are quickly depleted due to clearance of excess NAPQI, which enables hepatic proteins to become covalently modified by reactive metabolites and eventually results in hepatocyte necrosis. MW: 149.2. Purity ≥90% by HPLC