N-Acetyl-4-benzoquinone imine (NAPQI) is a cytochrome P450 3A4 and 2E1 metabolite of acetaminophen that can be toxic to the liver when acetaminophen is consumed in large doses. 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.
Reactant involved in:• ;Redox reactions1• ;Hydrohalogenation2• ;pH dependent reactions: in acidic media it is hydrolyzed, hydroxylated in alkaline media, and dimerized at intermediate pHs3• ;Mediation of acetaminophen hepatotoxicity4• ;Studies to identify the utility of acetaminophen for treating autoimmune disorders5
A toxic metabolite of Acetaminophen (A161220), which reacts with serum proteins.
A toxic metabolite of Acetaminophen, which reacts with serum proteins
N-Acetyl-4-benzoquinone imine (NAPQI) is a cytochrome P450 3A4 and 2E1 metabolite of acetaminophen that can be toxic to the liver when acetaminophen is consumed in large doses. 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.
ChEBI: N-acetyl-1,4-benzoquinone imine is a quinone imine and a ketoimine. It is functionally related to a 1,4-benzoquinone imine.
Human Endogenous Metabolite
[1] Y QIU A L B L Z Benet. Identification of the hepatic protein targets of reactive metabolites of acetaminophen in vivo in mice using two-dimensional gel electrophoresis and mass spectrometry.[J]. The Journal of Biological Chemistry, 1998, 273 28: 17940-17953. DOI:
10.1074/jbc.273.28.17940
