Acetylation of aromatic cysteine conjugates by recombinant human N-acetyltransferase 8.

Xenobiotica

a Department of Molecular and Cellular Biology , University of Guelph, Guelph , Ontario , Canada.

Published: March 2017

1. The mercapturic acid (MA) pathway is a metabolic route for the processing of glutathione conjugates to MA (N-acetylcysteine conjugates). An N-acetyltransferase enzyme, NAT8, catalyzes the transfer of an acetyl group from acetyl-CoA to the cysteine amino group, producing a MA, which is excreted in the urine. We expressed human NAT8 in HEK293T cells and developed an HPLC-MS method for the quantitation of the S-aryl-substituted cysteine conjugates and their MA. 2. We measured the activity of the enzyme for acetylation of benzyl-, 4-nitrobenzyl-, and 1-menaphthylcysteine substrates. 3. NAT8 catalyzed the acetylation of all three cysteine conjugates with similar Michaelis-Menten kinetics.

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http://dx.doi.org/10.1080/00498254.2016.1178410DOI Listing

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