Kinetic constants for recombinant human BChE, determined in 0.1 M potassium phosphate, pH 7.0, at 25°C for butyrylthiocholine and benzoylcholine and at 30°C for (−)-cocaine
| Human BChE | Butyrylthiocholine | ||||
|---|---|---|---|---|---|
| Km | Kss | b | kcat | bkcat | |
| μM | mM | min−1 | min−1 | ||
| Wild-type | 23 ± 2 | 1.4 ± 0.2 | 2.5 ± 0.1 | 33,900 ± 1,800 | 84,900 ± 4,600 |
| N68Y/Q119Y/A277W | 59 ± 10 | 3.4 ± 0.3 | 4.7 ± 0.4 | 11,700 ± 900 | 55,000 ± 4,500 |
| Q119Y | 11 ± 1 | 1.6 ± 0.6 | 10.9 ± 2.7 | 6,300 ± 1,700 | 69,000 ± 18,100 |
| Q119Y/V288F/A328Y | 26 ± 8 | 0.5 ± 0.1 | 2.5 ± 0.5 | 19,700 ± 800 | 49,200 ± 2,100 |
| E197Q | 83 ± 4 | 21 ± 12 | 1.6 ± 0.2 | 11,500 ± 200 | 18,500 ± 300 |
| V288F | 9 ± 1 | 0.3 ± 0.1 | 3.2 ± 1.1 | 14,100 ± 4,900 | 45,200 ± 15,700 |
| A328F | 20 ± 1 | 0.7 ± 0.3 | 1.2 ± 0.2 | 32,400 ± 1,000 | 38,900 ± 1,100 |
| A328Y | 15 ± 1 | 0.2 ± 0.2 | 1.2 ± 0.2 | 38,800 ± 8,400 | 48,500 ± 9,900 |
| F329A | 24 ± 4 | 1.3 ± 0.1 | 3.3 ± 0.2 | 21,200 ± 1,300 | 69,900 ± 4,400 |
| F329S | 27 ± 3 | 2.0 ± 0.4 | 2.4 ± 0.1 | 19,000 ± 1,000 | 45,500 ± 2,500 |
| Benzoylcholine | (−)-Cocaine | ||||
|---|---|---|---|---|---|
| Km | kcat | Km | kcat | kcat/Km | |
| μM | min−1 | μM | min−1 | M−1min−1 | |
| Wild-type | 8 ± 1 | 14,500 ± 200 | 14 ± 1 | 3.9 ± 0.1 | 280,000 |
| N68Y/Q119Y/A277W | 20 ± 1 | 5,500 ± 100 | 60 ± 12 | 1.7 ± 0.2 | 28,000 |
| Q119Y | 31 ± 1 | 10,600 ± 200 | 56 ± 10 | 2.0 ± 0.2 | 36,000 |
| Q119Y/V288F/A328Y | 23 ± 2 | 6,600 ± 200 | 33 ± 6 | 2.3 ± 0.2 | 70,000 |
| E197Q | 29 ± 2 | 7,200 ± 200 | 17 ± 1 | 0.1 ± 0.01 | 6,000 |
| V288F | 15 ± 1 | 11,700 ± 300 | 17 ± 2 | 1.0 ± 0.1 | 60,000 |
| A328F | 8 ± 2 | 11,800 ± 300 | 24 ± 4 | 5.8 ± 0.4 | 240,000 |
| A328Y | 12 ± 1 | 13,300 ± 400 | 9 ± 1 | 10.2 ± 0.4 | 1,130,000 |
| F329A | 10 ± 1 | 10,100 ± 200 | 128 ± 20 | 2.7 ± 1.0 | 21,000 |
| F329S | N/A | N/A | 41 ± 18 | 1.9 ± 0.3 | 46,000 |