Cocaine Metabolism Accelerated by a Re-Engineered Human Butyrylcholinesterase
- 1Molecular Neuroscience Program (H.S., S.B.), 2Department of Molecular Pharmacology and Experimental Therapeutics (H.S., Y.-P.P., S.B.), and 3Mayo Clinic Cancer Center (Y.-P.P.), Mayo Foundation for Medical Education and Research, Rochester, Minnesota; 4Eppley Institute and Department of Biochemistry and Molecular Neuroscience (O.L.), University of Nebraska Medical Center, Omaha, Nebraska; and 5Bruker Daltonics (M.L.S.), Billerica, Massachusetts
- Stephen Brimijoin, 200 First Street Southwest, Rochester, MN 55905. E-mail:brimijoi{at}mayo.edu
Abstract
Plasma butyrylcholinesterase (BChE) is important in the metabolism of cocaine, but natural human BChE has limited therapeutic potential for detoxication because of low catalytic efficiency with cocaine. Here we report pharmacokinetics of cocaine in rats treated with A328W/Y332A BChE, an excellent cocaine hydrolase designed with the aid of molecular modeling. Compared with wild-type BChE, this enzyme hydrolyzes cocaine with 40-fold improvedkcat (154 min−1 versus 4.1 min−1) and only slightly increasedKM (18 μM versus 4.5 μM). In rats given this hydrolase (3 mg/kg i.v.) 10 min before cocaine challenge (6.8 mg/kg i.v.), cocaine half-life was reduced from 52 min to 18 min. Mirroring the reductions of plasma cocaine were large increases in benzoic acid, a product of BChE-mediated cocaine hydrolysis. All other pharmacokinetic parameters confirmed a large, dose-dependent acceleration of cocaine removal by the injected cocaine hydrolase. These results show that A328W/Y332A, an efficient cocaine hydrolase in vivo as well as in vitro, might promote cocaine detoxication in a clinical setting.
Footnotes
- Abbreviations:
- BChE
- butyrylcholinesterase
- iso-OMPA
- tetraisopropyl pyrophosphoramide
- LC-MS
- liquid chromatography-mass spectrometry
- BE
- benzoylecgonine
- EME
- ecgonine methyl ester
- CL
- clearance
- Vss
- volume of distribution at steady state
- AUC0→∞
- area under the curve from time 0 to final sample
- AUMC0→∞
- area under the first moment curve from time 0 to final sample
- CLtotal
- total clearance from plasma
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- Received February 5, 2002.
- Accepted April 5, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
