What Are the Potential Sites of Protein Arylation by N Acetyl p benzoquinone Imine (NAPQI)? Chemical Research in Toxicology Alcohol and paracetamol are both processed through the liver. Paracetamol can form a toxic metabolite called NAPQI, which the body usually neutralises safely. But factors like heavy alcohol use, repeated dosing, fasting, Acetaminophen Toxicity: How Genetic Susceptibility Combines with Environmental Factors Problem 2: N acetyl para benzoquinone (NAPQI) is an oxidized TYLENOL [Aetaminophen] metabolism Cyp 3A4 and 2E1: CYP3A4 is the major Cytochrome P 450 [Cyp] enzyme that catalyzes acetaminophen oxidation into NAPQI in human Phase I liver detox. The other Cyp enzyme