Table 1.

Kinetic constants of the E. coli dsUDG and hTDG proteins for the excision of ɛC, uracil, and thymine (opposite to guanine)

Enzyme	Substrate*	Km, nM	kcat, min−1	kcat/Km, min × nM−1
dsUDG	ɛC/G†	2.5  ± 1.6	0.95  ± 0.22	0.38
	U/G	22.7  ± 8.6	0.17  ± 0.03	0.77  × 10−2
	T/G	26  ± 10	(0.43  ± 0.06) ×10−3	0.17  × 10−4
hTDG	ɛC/G	24.3  ± 14.9	(9.2  ± 1.7) ×10−3	0.38  × 10−3
	U/G	12  ± 5	(21  ± 3) ×10−3	1.73  × 10−3
	T/G	12.8  ± 4.9	(0.9  ± 0.1) ×10−3	0.071  × 10−3

^*Substrate concentration range 2.5–100 nM. 

^†Substrate concentration range 0.1–6 nM.