LeSaint Johnathan E, Hou Shurong, Chandar Nellore Bhanu, Kyomuhangi Annet, Wei Huimei, Zheng Fang, Zhan Chang-Guo
Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.
Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.
Chem Biol Interact. 2025 Aug 1;416:111552. doi: 10.1016/j.cbi.2025.111552. Epub 2025 May 8.
Organophosphate (OP) chemical warfare nerve agents and pesticides are potent, irreversible inhibitors of acetylcholinesterase (AChE), and paraoxon is often used as a surrogate compound in the studies of OP poisoning. For a truly effective treatment of OP poisoning, it is desirable that a protein-based OP bioscavenger can react with OP significantly faster than AChE reacting with OP to protect AChE from further inhibition reaction with OP. In the present study, our in vitro reactivity assays revealed that CocH3-Fc(M3), a potent cocaine hydrolase engineered from human butyrylcholinesterase (BChE), has a ∼20-fold improved bimolecular rate constant for the reaction with paraoxon compared to wild-type BChE. Due to the improved in vitro reactivity with paraoxon, CocH3-Fc(M3) at a modest dose of 25 mg/kg was able to effectively rescue all mice that had been injected with a lethal dose of 0.66 mg/kg paraoxon and accelerate the recovery of the mice from paraoxon-induced toxicity symptoms. All the in silico, in vitro, and in vivo data consistently suggest that CocH3-Fc(M3) can be used to effectively detoxify paraoxon.
有机磷酸酯（OP）类化学战神经毒剂和杀虫剂是乙酰胆碱酯酶（AChE）的强效、不可逆抑制剂，对氧磷常被用作OP中毒研究中的替代化合物。为了真正有效地治疗OP中毒，期望一种基于蛋白质的OP生物清除剂与OP的反应速度能显著快于AChE与OP的反应速度，以保护AChE免受与OP的进一步抑制反应。在本研究中，我们的体外反应性测定表明，由人丁酰胆碱酯酶（BChE）改造而来的强效可卡因水解酶CocH3-Fc(M3)，与对氧磷反应的双分子速率常数相比野生型BChE提高了约20倍。由于与对氧磷的体外反应性得到改善，中等剂量25mg/kg的CocH3-Fc(M3)能够有效挽救所有注射了致死剂量0.66mg/kg对氧磷的小鼠，并加快小鼠从对氧磷诱导的毒性症状中恢复。所有的计算机模拟、体外和体内数据一致表明，CocH3-Fc(M3)可用于有效解毒对氧磷。
