Open AccessFormation of 2‐Amino‐3‐methylimidazo[4,5‐ f ]quinoline‐ and 2‐Amino‐3,8‐dimethylimidazo[4,5‐ f ]quinoxaline‐sulfamates by cDNA‐expressed Mammalian Phenol Sulfotransferases
Author(s) -
Ozawa Shogo,
Nagata Kiyoshi,
Yamazoe Yasushi,
Kato Ryuichi
Publication year - 1995
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1995.tb03049.x
Subject(s) - cytosol , sulfotransferase , chemistry , sulfation , biochemistry , complementary dna , quinoxaline , quinoline , enzyme , stereochemistry , organic chemistry , gene
In rat liver cytosol systems, 2‐amino‐3‐methylimidazo[4,5‐ f ]quinoIine (IQ) and 2‐amino‐3,8‐dimethyl‐imidazo[4,5‐ f ]quinoxaline (MelQx) were converted into their sulfamates in the presence of 3′‐phosphoadenosine 5′‐phosphosulfate at rates of 51.2 and 50.7 pmol/min/mg cytosol in the male, and 23.7 and 22.5 pmol/min/mg cytosol in the female, respectively. IQ‐sulfamate formation was low (0.24 pmol/min/mg cytosol) in human liver cytosols, and MeIQx‐sulfamate was not detected (<0.1 pmol/ min/mg cytosol). These results suggest only a minor contribution of IQ‐ and MeIQx‐sulfamate formation to the detoxification of both heterocyclic amines in humans. Using sulfotransferase cDNA‐expression systems, a rat ST1A1 arylsulfotransferase has been shown to catalyze the formation of the sulfamates, suggesting a role of the ST1A type of sulfotransferase in the N‐sulfation of heterocyclic amines.