Effects of uric acid on nitrosation of N-acetylcysteine by diethylamine NONOate and N-acetyl-N-nitrosotryptophan.
Uric acid of human plasma concentration accelerated nitrosation of N-acetylcysteine by diethylamine NONOate at neutral pH, but diminished that of N-acetyltryptophan. Uric acid also accelerated nitrosation of N-acetylcysteine by N-acetyl-N-nitrosotryptophan, having a nitroso group on the nitrogen atom of the indole ring. N-Acetyl-S-nitrosocysteine was stable even in the presence of uric acid and N-acetyltryptophan at neutral pH, while decomposition of N-acetyl-N-nitrosotryptophan was accelerated by uric acid and N-acetylcysteine. The results indicate that uric acid receives a nitroso group from diethylamine NONOate or N-acetyl-N-nitrosotryptophan, and passes it to the thiol group of N-acetylcysteine resulting in N-acetyl-S-nitrosocysteine. This implies that uric acid may act as an effective transporter of nitric oxide to thiols resulting in accumulation of nitrosothiols in humans.
Suzuki
Toshinori
T
School of Pharmacy, Shujitsu University. tsuzuki@shujitsu.ac.jp
Naka
Atsushi
A
Kimura
Haruka
H
D000111:Acetylcysteine / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D004048:Diethylamines / Q000737:chemistry*; D009602:Nitrosamines / Q000737:chemistry*; D015538:Nitrosation; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000737:chemistry; D014527:Uric Acid / Q000737:chemistry*
D001391:Azo Compounds; D004048:Diethylamines; C511420:N-acetyl-N-nitrosotryptophan; D009602:Nitrosamines; C505253:diethylamine diazeniumdiolate; D014527:Uric Acid; D014364:Tryptophan; D000111:Acetylcysteine