Table 1. Enzyme kinetic parameters of wild-type (WT) and mutant EGFR kinases.

All experiments were performed in triplicate (n = 3). Km[ATP], Michaelis constant for ATP; Ki, inhibition constant; SD, standard deviation.

EGFR kinaseFold activity
versus WT
Km[ATP] (μM),
average
(SD)
Ki[gefitinib]
(nM), average
(SD)
Ki/Km
(×10−3)
WT1.004.98 (±1.2)16.4 (±0.2)3.29
L858R33.1268.5 (±3.4)6.4 (±0.8)0.09
D770_N771insNPG4.9336.8 (±7.4)25.7 (±4.3)0.69
A763_Y764insFQEA8.9619.2 (±0.9)2.5 (±0.3)0.13