Closed Head Injury Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
Toxicol In Vitro. 2011 Jun;25(4):905-13. doi: 10.1016/j.tiv.2011.02.012. Epub 2011 Mar 5.
Paraoxonase 1 (PON1) has been described as a potential catalytic bioscavenger due to its ability to hydrolyze organophosphate (OP) insecticides and nerve agents. In vitro catalytic efficiency of purified human and rabbit serum PON1 against different OP substrates was compared to human recombinant PON1, expressed in Trichoplusia ni larvae. Highly purified human and rabbit serum PON1s were prepared by multiple chromatography methods. Purified enzymes showed higher catalytic activity with the substrate p-nitrophenyl acetate compared to diethyl paraoxon. The hydrolyzing potential of PON1s against multiple OPs was evaluated by using an in vitro acetylcholinesterase back-titration assay. Significant differences in the catalytic efficiency of all the three PON1s with regard to various OP substrates were observed. Purified PON1s showed higher catalytic activity towards diisopropylfluorophosphate followed by diethylparaoxon compared to dimethyl paraoxon. Heat inactivation or incubation of PON1 with specific inhibitor resulted in complete loss of the enzyme catalytic activity indicating that OP hydrolysis was intrinsic to PON1. In conclusion, purified PON1s from multiple sources show significant differences in the catalytic activity against several OP substrates. These results underscore the importance of systematic analysis of candidate PON1 molecules for developing as an effective catalytic bioscavenger against toxic OPs and chemical warfare nerve agents.
对氧磷酶 1（PON1）因其能够水解有机磷（OP）杀虫剂和神经毒剂而被描述为一种有潜力的催化生物清除剂。比较了纯化的人和兔血清 PON1 对不同 OP 底物的体外催化效率与在三化螟幼虫中表达的人重组 PON1。通过多种色谱方法制备了高度纯化的人和兔血清 PON1。与二乙基对氧磷相比，纯化的酶对 p-硝基苯乙酸酯的催化活性更高。通过体外乙酰胆碱酯酶反滴定测定评估了 PON1 对多种 OP 的水解潜力。观察到所有三种 PON1 对各种 OP 底物的催化效率存在显著差异。与二甲氧基亚砜相比，纯化的 PON1 对二异丙基氟膦的催化活性更高，随后是二乙基对氧磷。PON1 的热失活或与特定抑制剂孵育会导致酶催化活性完全丧失，表明 OP 水解是 PON1 的固有特性。总之，来自多种来源的纯化 PON1 在对几种 OP 底物的催化活性方面存在显著差异。这些结果强调了对候选 PON1 分子进行系统分析以开发针对有毒 OP 和化学战神经毒剂的有效催化生物清除剂的重要性。
