RT Journal Article SR Electronic T1 The Ability of Bacterial Cocaine Esterase to Hydrolyze Cocaine Metabolites and their Simultaneous Quantification Using High Performance Liquid Chromatography-Tandem Mass Spectrometry JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP mol.111.074534 DO 10.1124/mol.111.074534 A1 Remy Brim A1 Kathleen R Noon A1 Gregory T Collins A1 Joseph Nichols A1 Diwahar Narasimhan A1 Roger K Sunahara A1 James H Woods YR 2011 UL http://molpharm.aspetjournals.org/content/early/2011/09/01/mol.111.074534.abstract AB Cocaine toxicity is a widespread problem in the United States, responsible for over half a million emergency department visits a year. There is currently no FDA-approved pharmacotherapy to directly treat cocaine toxicity. To this end, we have developed a mutant bacterial cocaine esterase (DM-CocE), which has been previously shown to rapidly hydrolyze cocaine into inert metabolites preventing and reversing toxicity with limited immunogenic potential. Herein we describe the ability of DM-CocE to hydrolyze the active cocaine metabolites norcocaine and cocaethylene, and its inability to hydrolyze benzoylecgonine. DM-CocE hydrolyzes norcocaine and cocaethylene with 58% and 45% of its catalytic efficiency for cocaine in vitro as measured by a spectrophotometric assay. We have developed a mass spectrometry method to simultaneously detect cocaine, benzoylecgonine, norcocaine and ecgonine methyl ester to quantify the effect of DM-CocE on normal cocaine metabolism in vivo. DM-CocE administered to rats 10 minutes after a convulsant dose of cocaine alters the normal metabolism of cocaine; rapidly decreasing circulating levels of cocaine and norcocaine while increasing ecgonine methyl ester formation. Benzoylecgonine was not hydrolyzed in vivo, but circulating concentrations were reduced, suggesting that DM-CocE may bind and sequester this metabolite. These findings suggest that DM-CocE may reduce cocaine toxicity by eliminating active and toxic metabolites along with the parent cocaine molecule.