Table 1. Relative rate constants obtained from multiple substrate kinetics.

	40T/50U		40U/50T		Average
	A/G : T/G	U/G : T/G	A/G : T/G	U/G : T/G	A/G : T/G	U/G : T/G
WT	0.019 ± 0.003	1.34 ± 0.09	0.017 ± 0.001	1.20 ± 0.05	0.018	1.27
L187Q	0.42 ± 0.12	2.12 ± 0.08	0.49 ± 0.03	1.83 ± 0.04	0.46	1.98
A50V	0.13 ± 0.01	2.96 ± 0.32	0.15 ± 0.01	2.92 ± 0.38	0.14	2.94
A50V/L187Q	2.22 ± 0.34	1.97 ± 0.38	1.94 ± 0.16	1.74 ± 0.20	2.08	1.85

Values are given as averages of three independent measurements with standard deviations.