Chloramphenicol, at concentrations greater than 0.1 g/liter (0.3 mM), inhibited the denitrifying enzyme activity (DEA) of slurries of humisol and sandy loam soils by disrupting the activity of existing nitrate reductase enzymes. When the concentration of chloramphenicol was increased from 0.1 to 2.0 g/liter (6.0 mM), the rate of nitrite production from nitrate decreased by 25 to 46%. The rate of NO production from nitrate decreased by 20 to 39%, and the rate of N2O production from nitrate, in the presence of acetylene (DEA), decreased by 21 to 61%. The predicted values of DEA at 0 g of chloramphenicol/liter computed from linear regressions of DEA versus chloramphenicol concentration were 18 to 43% lower than DEA measurements made in the absence of chloramphenicol and within a few per cent of DEA rates measured in the presence of 0.1 g of chloramphenicol/liter. We conclude that DEA assays should be carried out with a single (0.1-g/liter) chloramphenicol concentration. Chloramphenicol at concentrations greater than 0.1 g/liter inhibits the activity of existing denitrifying enzymes and should not be used in DEA assays.
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机译：浓度大于0.1 g / l（0.3 mM）的氯霉素通过破坏现有的硝酸还原酶的活性，抑制了humisol和沙质壤土的浆液的反硝化酶活性（DEA）。当氯霉素的浓度从0.1升至2.0克/升（6.0毫米）时，硝酸盐中亚硝酸盐的产生率降低了25％至46％。在乙炔（DEA）存在下，硝酸盐的NO生成量降低了20％至39％，硝酸盐中的N2O生成速率降低了21％至61％。由DEA对氯霉素浓度的线性回归计算得出的0 g氯霉素/升下DEA的预测值比不存在氯霉素的DEA测量值低18％至43％，并且在有氯霉素存在时测得的DEA值在百分之几以内0.1克氯霉素/升。我们得出结论，DEA分析应使用单一浓度（0.1克/升）的氯霉素进行。浓度大于0.1 g / L的氯霉素会抑制现有反硝化酶的活性，因此不得用于DEA分析。
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