多种有机磷剂抗性品系淡色库蚊羧酸酯酶的提纯及其对14C—马拉硫磷的降介作用

PURIFICATION OF CARBOXYLESTERASE AND ENZYMATIC DEGRADATION OF 14C-MALATHION IN MULTI-ORGANOPHOSPHATE-RESISTANT MOSQUITO(CU LEX PI PI ENS P ALLEN S COQ.)

DEAE——纤维素柱层析及其连续梯度洗脱法用于分离纯化淡色库蚊有机磷剂品系的特征性羧酸酯酶(E),分离纯度达150倍;经聚丙烯酰胺凝胶园盘电泳鉴测确系一条单一的E带,不存在其它酯酶。 纯化的E能降介[C—甲基]马拉硫磷,所生成的羧酸衍生物量与加入的E量成线性关系。此直接证明了抗性品系体内E合成量的增加是其产生有机磷抗性的主要机理之一。

The carboxylesterase associated with resistance was separated from other esterases in homogenates of resistant mosquito adults (Culex pipiens pallens Coq.) by a column chromatography of DEAE-eellulose elutcd with a linear 0-0.35M-NaCl gradient in 400 ml of 0.02M tris/HCl buffer (pH 7.05), The purified enzyme was examined for its enzyme compositions by using a polyacrylamide gel disc electrophoresis. The results showed that the purified enzyme was 150 times more pure than the crude homogenates and is a single band E9 without overlapped phosphatase. The enzyme activity corresponded with the protein peak. Radiometric studies showed that this purified E8 band was able to degrade I4C-malathion and the main products carboxylic acid derivatives correlated with the amounts of E8 These facts evidenced that the carboxylesterase E8 is an important factor in the mechanism of resistance of Cules pipiens pallens Coq. to organophosphorus insecticides.