Esterase Specificity and Sensitivity to Organophosphorus and Carbamate Pesticides: Factors Affecting Determination by Thin Layer Chromatography

Abstract

Abstract Beef liver esterase was much more sensitive to organophosphorus pesticides than pig liver esterase, whereas the opposite was true for carbamates. Marked difference in specificity was noted for the inhibition of beef and pig esterases due to malathion and parathion. Inhibition of beef and pig liver esterases attributed to ethion was due to conversion of ethion to a product under the lights in the laboratory. However, inhibition of beef esterase attributed to parathion was due to conversion of parathion to paraoxon by the beef extract. Although bee head esterase was most sensitive to organophosphorus and carbamate pesticides, it had disadvantages over pig or beef liver esterase. The bee esterase was approximately 8 or 33 times less active than the same amount of beef or pig liver esterase. The bee brei (100 ml) was sufficient to spray 40 thin layer plates only, whereas the pig and beef liver extracts (1 L each) were sufficient to spray 10,000 and 2,500 plates, respectively. The technique was also used to detect pesticides in the presence of pea and carrot extractives. Advantages of the thin layer chromatographic-enzyme inhibition technique are discussed.