Skip to main content
. Author manuscript; available in PMC: 2015 Jun 15.
Published in final edited form as: Biochem J. 2014 Jun 15;460(3):447–457. doi: 10.1042/BJ20140360

Table 1.

Kinetic parameters determined in vitro for (−)-cocaine, norcocaine and cocaethylene hydrolyses catalyzed by wild-type BChE and its mutants.

Substrate Enzymea KM (μM) kcat (min−1) kcat/KM (M−1min−1) RCEd
(−)-Cocaineb WT BChE 4.5 4.1 9.11 × 105 1
E14-3 3.1 3,060 9.87 × 108 1,080
E12-7 3.1 5,700 1.84 × 109 2,020
Norcocaineb WT BChE 15 2.8 1.87 × 105 1
E14-3 12 766 6.38 × 107 343
E12-7 13 2,610 2.01 × 108 1,080
Cocaethylenec WT BChE 7.5 3.3 4.40 × 105 1
E14-3 8.0 1,820 2.28 × 108 517
E12-7 9.5 3,600 3.79 × 108 861
a

The enzyme under the study was wild-type human BChE (WT BChE), A199S/S287G/A328W/Y332G mutant (E14-3), (CocH2), or A199S/F227A/S287G/A328W/Y332G mutant (E12-7).

b

Data for wild-type BChE against (−)-cocaine came from reference [12], data for E14-3 against (−)-cocaine came from reference [25], data for CocH3 against (−)-cocaine came from reference [22], and data for all enzymes against norcocaine came from reference [[26]].

c

All of the kinetic data for cocaethylene were determined in the present study for the first time.

d

RCE refers to the relative catalytic efficiency (kcat/KM), i.e. the ratio of the kcat/KM value of the mutant to that of wild-type BChE against the same substrate.