NAPQI

NAPQI is the toxic metabolite of Acetaminophen (HY-66005). NAPQI is also an inhibitor of enzymes in the vitamin K cycle. NAPQI is rapidly detoxified by glutathione (GSH), but in situations of GSH deficiency, excess NAPQI reacts with cysteine residues in proteins, causing cell death and toxicity in the liver[1][2].

[1]Jiang D, et al. Organ-Specific Screening for Protein Damage Using Magnetic Bead Bioreactors and LC-MS/MS. Anal Chem. 2020 Apr 7;92(7):5337-5345.|[2]Thijssen HH, et al. Paracetamol (acetaminophen) warfarin interaction: NAPQI, the toxic metabolite of paracetamol, is an inhibitor of enzymes in the vitamin K cycle. Thromb Haemost. 2004 Oct;92(4):797-802.|[3]Walker V, et al. The acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI) inhibits glutathione synthetase in vitro; a clue to the mechanism of 5-oxoprolinuric acidosis? Xenobiotica. 2017 Feb;47(2):164-175.|[4]Kalinec GM, et al. Acetaminophen and NAPQI are toxic to auditory cells via oxidative and endoplasmic reticulum stress-dependent pathways. Hear Res. 2014 Jul;313:26-37.