Kinetic characterization of human butyrylcholinesterase mutants for the hydrolysis of cocaethylene

Shurong Hou, Max Zhan, Xirong Zheng, Chang Guo Zhan, Fang Zheng

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


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 (κcat and KM) 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 (κcat =3.3 min-1, K M =7.5 μM and κcat/KM =4.40×105 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 (κcat =3600 min-1, KM =9.5 μM and κcat/KM =3.79×108 M-1 min-1). It has been demonstrated that E12-7 as an exogenous enzyme can indeed rapidlymetabolize 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.

Original languageEnglish
Pages (from-to)447-457
Number of pages11
JournalBiochemical Journal
Issue number3
StatePublished - Jun 15 2014


  • Butyrylcholinesterase
  • Drug abuse
  • Hydrolysis
  • Kinetics
  • Protein drug

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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