Table 7. Steady-State Kinetic Parameters for dNTP Incorporation Opposite Abasic Site by Wild-Type and Variant hPols ι(1-445) in the Presence of 0.15 mM Mn²⁺.

pol ι(1–445)	dNTP	Km (μM)	kcat (s–1)	kcat/Km (s–1 mM–1)	dNTP selectivity ratioa	relative efficiencyb
wild-type	A	0.68 ± 0.04	0.012 ± 0.0001	18	0.18
	T	1.5 ± 0.1	0.064 ± 0.001	43	0.43
	G	0.29 ± 0.06	0.029 ± 0.001	100	1	1
	C	2.8 ± 0.1	0.066 ± 0.001	24	0.24
Δ1–25	A	0.50 ± 0.06	0.010 ± 0.003	20	0.22
	T	1.1 ± 0.1	0.024 ± 0.001	22	0.24
	G	0.099 ± 0.005	0.0091 ± 0.0001	92	1	0.92
	C	0.98 ± 0.08	0.043 ± 0.001	44	0.48
ΔD17	A	0.83 ± 0.13	0.016 ± 0.001	19	0.31
	T	1.8 ± 0.2	0.048 ± 0.001	27	0.44
	G	0.34 ± 0.04	0.021 ± 0.0004	62	1	0.62
	C	1.8 ± 0.3	0.11 ± 0.004	61	0.98
R96G	A	1.9 ± 0.3	0.011 ± 0.0004	5.8	0.76
	T	1.9 ± 0.2	0.0088 ± 0.0002	4.6	0.61
	G	0.49 ± 0.06	0.0037 ± 0.0001	7.6	1	0.076
	C	3.4 ± 0.3	0.015 ± 0.0004	4.4	0.58
I261M	A	0.35 ± 0.05	0.021 ± 0.001	60	0.50
	T	1.3 ± 0.09	0.026 ± 0.0004	20	0.17
	G	0.27 ± 0.02	0.032 ± 0.001	120	1	1.2
	C	2.5 ± 0.4	0.050 ± 0.002	20	0.17
E276K	A	0.72 ± 0.11	0.017 ± 0.001	24	0.39
	T	2.7 ± 0.3	0.028 ± 0.0007	10	0.16
	G	0.34 ± 0.02	0.021 ± 0.0002	62	1	0.62
	C	2.2 ± 0.1	0.041 ± 0.0005	19	0.31
Y374N	A	0.71 ± 0.09	0.026 ± 0.001	37	0.38
	T	2.0 ± 0.2	0.082 ± 0.002	41	0.42
	G	0.39 ± 0.03	0.038 ± 0.001	97	1	0.97
	C	3.3 ± 0.3	0.047 ± 0.001	14	0.14

^adNTP selectivity ratio, calculated by dividing k_cat/K_m for each dNTP incorporation by the highest k_cat/K_m for dNTP incorporation opposite the abasic site. All values are presented to two significant digits.

^bRelative efficiency, calculated by dividing k_cat/K_m of each pol ι(1–445) for dGTP incorporation opposite the abasic site by k_cat/K_m of wild-type pol ι(1–445) for dGTP incorporation opposite the abasic site.