Hanke D W, Overton M A
U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland.
J Toxicol Environ Health. 1991 Sep;34(1):141-56. doi: 10.1080/15287399109531554.
Kinetic constants for selected phosphonate and phosphinate inhibitors of fetal bovine serum acetylcholinesterase (FBS AChE; EC 3.1.1.7), bovine caudate nucleus AChE (BCN AChE), and eel AChE have been determined. Oxime reactivation of the phosphylated enzymes has also been evaluated. In general, a rank order with respect to organophosphorus compound (OP) inhibition of the enzymes was observed: soman (pinacolyl methylphosphonofluoridate) was found to be the most potent inhibitor, and 4-nitrophenyl methyl(phenyl)phosphinate (PMP) the least potent. On average the bimolecular rate constant for soman inhibition of eel AChE was nearly twofold greater (9.3 x 10(7) M-1 s-1) than that for FBS AChE (5.5 x 10(7) M-1 s-1) and nearly fourfold greater than that for BCN AChE (2.2 x 10(7) M-1 s-1). In addition, 4-nitrophenyl chloromethyl(phenyl)phosphinate (CPMP) inhibition of eel AChE on average was nearly 10-fold greater than FBS AChE and three orders of magnitude greater than BCN AChE. The oxime HI-6 reactivated soman phosphonylated enzymes to a considerably greater extent than other oximes, and FBS AChE was notably more responsive to HI-6 than to other oximes. The individual mean values of the ki for each inhibitor in each class (phosphonate or phosphinate) were different with respect to each AChE, which may be a reflection of differences in enzyme configuration, whereas the general rank order of inhibitor potency within each class, reflected by the ki, was similar with respect to each AChE, which may be related to similar active centers. In general, oxime potency and some rank order varied with each inhibitor and with each AChE, although there was some similarity in oxime rank order between the two mammalian AChEs. Overall, the data support the selection of FBS AChE as the enzyme of choice for in vitro testing of OP inhibitors and reactivators.
已测定了选定的膦酸酯和次膦酸酯对胎牛血清乙酰胆碱酯酶（FBS AChE；EC 3.1.1.7）、牛尾状核乙酰胆碱酯酶（BCN AChE）和鳗鱼乙酰胆碱酯酶的动力学常数。还评估了磷酸化酶的肟再活化作用。一般来说，观察到有机磷化合物（OP）对这些酶的抑制作用存在一个排序：发现梭曼（频哪基甲基膦酰氟）是最有效的抑制剂，而4-硝基苯基甲基（苯基）次膦酸酯（PMP）是最无效的。平均而言，梭曼抑制鳗鱼乙酰胆碱酯酶的双分子速率常数（9.3×10⁷ M⁻¹ s⁻¹）比抑制FBS AChE的双分子速率常数（5.5×10⁷ M⁻¹ s⁻¹）几乎大两倍，比抑制BCN AChE的双分子速率常数（2.2×10⁷ M⁻¹ s⁻¹）几乎大四倍。此外，4-硝基苯基氯甲基（苯基）次膦酸酯（CPMP）对鳗鱼乙酰胆碱酯酶的抑制作用平均比FBS AChE大近10倍，比BCN AChE大三个数量级。肟HI-6使梭曼磷酸化酶再活化的程度比其他肟大得多，并且FBS AChE对HI-6的反应明显比对其他肟更敏感。每类（膦酸酯或次膦酸酯）中每种抑制剂的ki个体平均值因每种乙酰胆碱酯酶而异，这可能反映了酶构型的差异，而由ki反映的每类抑制剂效力的一般排序对于每种乙酰胆碱酯酶是相似的，这可能与相似的活性中心有关。一般来说，肟的效力和一些排序因每种抑制剂和每种乙酰胆碱酯酶而异，尽管两种哺乳动物乙酰胆碱酯酶之间在肟的排序上有一些相似性。总体而言，这些数据支持选择FBS AChE作为体外测试OP抑制剂和再活化剂的首选酶。
