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This study was designed to assess the effects of aspirin on arylamine N-acetyltransferase (NAT) activities in the bacterium Klebsiella pneumoniae using high performance liquid chromatography to measure the acetylation of 2-aminofluorene (2-AF) with or without aspirin. Cytosols or suspensions of K. pneumoniae with or without specific concentrations of aspirin co-treatment showed different percentages of 2-AF acetylation. The data indicated that there was decreased NAT activity associated with increased levels of aspirin in K. pneumoniae cytosols and in intact bacteria. For the cytosol examination, the apparent values of Km and Vmax decreased 0.59- and 0.58-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. For the intact bacteria examination, the apparent values of Km and Vmax decreased 0.60- and 0.67-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. This report is the first demonstration to show that aspirin can decrease N-acetyltransferase activity in the bacterium K. pneumoniae.

The N‐acetyltransferase activity was determined in 58 common fruits and vegetables. The assay was based on acetylation of 2‐aminofluorene or p‐amino‐benzoic acid, followed by high pressure liquid chromatographic analysis of products and remaining nonacetylated substrate. The highest specific activities were observed in Balsam pear which contained 17.37 ± 1.45 N‐acetyl aminofluorene nmole/min/mg protein and 46.27 ± 6.87 N‐acetyl p‐aminobenzoic acid nmole/min/mg protein. N‐acetyltransferase activities within the remaining 57 foodstuffs analyzed ranged from none detected to 3.39 ± 0.72 N‐acetyl aminofluorene nmole/min/mg protein and none detected to 32.45 ± 6.55 N‐acetyl p‐aminobenzoic acid nmole/min/mg protein. This is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in common foodstuffs.