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RESEARCH PRODUCT

EnzymesIn Vitro as indicators for pesticides: An examination

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Pesticides—a serious problem especially for drinking water quality—frequently are potent inhibitors of enzymes in their target organisms. As the established chemical analyses of pesticides are time-consuming, complicated, and expensive, so-called screening methods are urgently needed. For this purpose the sensitivity of 13 different enzymes was tested in vitro by inhibiting their kinetic rates and/or substrate conversions by 16 pesticides (herbicides and fungicides). Because of the stabilization and resulting low sensitivity of enzymes commercially available—especially in test kits—it was necessary to vary the test conditions and to develop special methods for detecting enzymatic inhibitions. It was shown that the sensitivity to pesticides of the different enzymes varies in a wide range, partly in irrelevant high concentrations. Four enzymes seem to be suitable for inhibition tests, but need to be checked before practical application. The enzyme aldehyde dehydrogenase (AlDh), isolated from yeasts, was very sensitive to ethendithiocarbamates. Therefore an inhibition test could be developed to detect this class of pesticides in a range of some μg/L. The AlDh inhibition test is the first part of an enzymatic screening system for pesticide pollution in water. © 1992 John Wiley & sons, Inc.