A simple colorimetric method for the simultaneous determination of N-acetylcysteine and cysteine.
The widespread use of N-acetylcysteine as an antioxidant and a precursor for tissue cysteine creates a need for a simple method that measures both and distinguishes them from one another. We describe a procedure based on the use of the enzyme acylase, which hydrolyzes N-acetylcysteine to cysteine. Cysteine is subsequently measured with a specific colorimetric procedure. Unhydrolyzed N-acetylcysteine gives only a weak colorimetric response (11.5% that for cysteine); after hydrolysis, however, the two are equivalent. Hence, N-acetylcysteine can be distinguished by the enhanced response after hydrolysis.
Department of Neurology and Neurobiology Research Center, Mount Sinai School of Medicine of the City University of New York, New York 10029, USA.
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Ogwu
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Cohen
D000111:Acetylcysteine / Q000032:analysis*; D000581:Amidohydrolases; D000818:Animals; D000975:Antioxidants; D003124:Colorimetry / Q000379:methods*; D003545:Cysteine / Q000032:analysis*; D013552:Swine
D000975:Antioxidants; D000581:Amidohydrolases; C019665:amidase; D003545:Cysteine; D000111:Acetylcysteine