title: Metabolic Enzymes of Cocaine Metabolite Benzoylecgonine.
abstract: Cocaine is one of the most addictive drugs without a U.S. Food and Drug Administration (FDA)-approved medication. Enzyme therapy using an efficient cocaine-metabolizing enzyme is recognized as the most promising approach to cocaine overdose treatment. The actual enzyme, known as RBP-8000, under current clinical development for cocaine overdose treatment is our previously designed T172R/G173Q mutant of bacterial cocaine esterase (CocE). The T172R/G173Q mutant is effective in hydrolyzing cocaine but inactive against benzoylecgonine (a major, biologically active metabolite of cocaine). Unlike cocaine itself, benzoylecgonine has an unusually stable zwitterion structure resistant to further hydrolysis in the body and environment. In fact, benzoylecgonine can last in the body for a very long time (a few days) and, thus, is responsible for the long-term toxicity of cocaine and a commonly used marker for drug addiction diagnosis in pre-employment drug tests. Because CocE and its mutants are all active against cocaine and inactive against benzoylecgonine, one might simply assume that other enzymes that are active against cocaine are also inactive against benzoylecgonine. Here, through combined computational modeling and experimental studies, we demonstrate for the first time that human butyrylcholinesterase (BChE) is actually active against benzoylecgonine, and that a rationally designed BChE mutant can not only more efficiently accelerate cocaine hydrolysis but also significantly hydrolyze benzoylecgonine in vitro and in vivo. This sets the stage for advanced studies to design more efficient mutant enzymes valuable for the development of an ideal cocaine overdose enzyme therapy and for benzoylecgonine detoxification in the environment.
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Xiabin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Xirong
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Max
authors.initials: M
authors.lastname: Zhan
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Ziyuan
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Chang-Guo
authors.initials: CG
authors.lastname: Zhan
authors.affiliation: Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , 789 South Limestone Street, Lexington, Kentucky 40536, United States.
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002091:Butyrylcholinesterase / Q000378:metabolism* / Q000627:therapeutic use; D003042:Cocaine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics; D019970:Cocaine-Related Disorders / Q000188:drug therapy; D062787:Drug Overdose / Q000188:drug therapy; D006801:Humans; D008658:Inactivation, Metabolic; D051381:Rats
chemical_list: C005618:benzoylecgonine; D002091:Butyrylcholinesterase; D003042:Cocaine