Kinetic characterization of human butyrylcholinesterase mutants for the hydrolysis of cocaethylene
| Autor: | Shurong Hou, Chang-Guo Zhan, Max Zhan, Xirong Zheng, Fang Zheng |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Stereochemistry Endogeny Alcohol CHO Cells Biochemistry Catalysis Article Toxicology Cocaine-Related Disorders chemistry.chemical_compound Hydrolysis Cricetulus Cocaethylene Cocaine medicine Animals Humans Molecular Biology Butyrylcholinesterase chemistry.chemical_classification Ethanol Cell Biology Rats Norcocaine Molecular Docking Simulation Kinetics HEK293 Cells Enzyme chemistry medicine.drug |
| Zdroj: | Biochemical Journal. 460:447-457 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | It is known that the majority of cocaine users also consume alcohol. Alcohol can react with cocaine to produce a significantly more cytotoxic compound, cocaethylene. Hence a truly valuable cocaine-metabolizing enzyme as treatment for cocaine abuse/overdose should be efficient for not only cocaine itself, but also cocaethylene. The catalytic parameters ( k cat and K M ) of human BChE (butyrylcholinesterase) and two mutants (known as cocaine hydrolases E14-3 and E12-7) for cocaethylene are characterized in the present study, for the first time, in comparison with those for cocaine. On the basis of the obtained kinetic data, wild-type human BChE has a lower catalytic activity for cocaethylene ( k cat =3.3 min −1 , K M =7.5 μM and k cat / K M =4.40×10 5 M −1 ·min −1 ) compared with its catalytic activity for (−)-cocaine. E14-3 and E12-7 have a considerably improved catalytic activity against cocaethylene compared with the wild-type BChE. E12-7 is identified as the most efficient enzyme for hydrolysing cocaethylene in addition to its high activity for (−)-cocaine. E12-7 has an 861-fold improved catalytic efficiency for cocaethylene ( k cat =3600 min −1 , K M =9.5 μM and k cat / K M =3.79×10 8 M −1 ·min −1 ). It has been demonstrated that E12-7 as an exogenous enzyme can indeed rapidly metabolize cocaethylene in rats. Further kinetic modelling has suggested that E12-7 with an identical concentration as that of the endogenous BChE in human plasma can effectively eliminate (−)-cocaine, cocaethylene and norcocaine in simplified kinetic models of cocaine abuse and overdose associated with the concurrent use of cocaine and alcohol. |
| Databáze: | OpenAIRE |
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