. Author manuscript; available in PMC: 2012 Jun 3.

Published in final edited form as: J Mol Biol. 2011 Apr 6;409(2):101–112. doi: 10.1016/j.jmb.2011.03.071

Table 4.

Summary of the kinetic parameters for FLAG-DGKε WT and its L438I and L431I mutants. Results are presented as the mean ±S.D. Although the measured activity at one substrate concentration did not show differences in substrate specificity (Fig.1), a more complete analysis of the kinetics does clearly illustrate that both k_cat, that represents the catalytic rate constant, as well as k_cat/K_m, that represents the pseudo first order rate constant at low substrate concentrations, are affected by the mutations, particularly for the SAG substrate (see Fig. 7 for the graphic representation of Table 4).

	K_m, mol%	k_cat, sec⁻¹	k_cat/K_m, sec⁻¹mol%⁻¹
FLAG-DGKε WT
SAG	2.44 ± 0.14	10.2 ± 0.3	4.16 ± 0.14
SLG	7.0 ± 1.4	4.6 ± 0.6	0.66 ± 0.11

FLAG-DGKε L438I
SAG	1.88 ± 0.15	2.24 ± 0.07	1.19 ± 0.05
SLG	2.9 ± 0.5	1.56 ± 0.09	0.54 ± 0.04

FLAG-DGKε L431I
SAG	2.4 ± 0.6	2.1 ± 0.2	0.91 ± 0.14
SLG	5.1 ± 1.2	2.7 ± 0.4	0.53 ± 0.09