Table 1

Steady-state kinetic constants for Pro-254 ecTS variants

Enzyme	k_cat	K_m(dUMP)^1-a	K_m(CH₂H₄PteGlu)^1-b	k_cat/K_m(dUMP)	k_cat/K_m(CH₂H₄PteGlu)
	s⁻¹	μM	μM
WtecTS	2.1	1.2	11	1.8	0.19
P254G	2.0	1.5	12	1.3	0.17
P254F	1.8	1.8	18	1.0	0.10
P254S	1.9	2.7	10	0.70	0.19
P254D	1.5	3.4	118	0.44	0.013

All values were obtained in triplicate. The standard errors are <10% of the reported values.

↵1-a Determined in the presence of 100 μM CH₂H₄PteGlu except for P254D, which was determined in the presence of 500 μM CH₂H₄PteGlu.
↵1-b Determined in the presence of 100 μM dUMP.