Table 3.

Kinetic parameters for nucleotide incorporation into gapped or recessed DNA catalyzed by Pol β at 37 °C

dNTP	kp(s−1)	Kd(µM)	kp/Kd(µM−1s−1)	Efficiency ratioa	Fidelityb
21-19/41mer (1-nucleotide gap)
dGTP	18.8 ± 0.4	8.7 ± 0.4	2.2	-
dCTP	0.059 ± 0.002	140 ± 20	4.2 × 10−4	-	1.9 × 10−4
dATP	0.32 ± 0.02	280 ± 60	1.1 × 10−3	-	5.3 × 10−4
dTTP	0.27 ± 0.01	330 ± 40	8.2 × 10−4	-	3.7 × 10−4
21-19/42mer (2-nucleotide gap)
dGTP	39 ± 1	12 ± 2	3.3	1
dCTP	0.0153 ± 0.0002	34 ± 3	4.5 × 10−4	1	1.4 × 10−4
dATP	0.212 ± 0.009	200 ± 20	1.1 × 10−3	1	3.3 × 10−4
dTTP	0.173 ± 0.009	340 ± 50	5.1 × 10−4	2 ↓	1.6 × 10−4
21-19/45mer (5-nucleotide gap)
dGTP	36 ± 2	100 ± 10	3.6 × 10−1	6 ↓
dCTP	0.065 ± 0.002	450 ± 30	1.4 × 10−4	3 ↓	4.0 × 10−4
dATP	0.0188 ± 0.0006	540 ± 40	3.5 × 10−5	33 ↓	9.7 × 10−5
dTTP	0.0117 ± 0.0008	900 ± 100	1.3 × 10−5	63 ↓	3.6 × 10−5
21-19/47mer (7-nucleotide gap)
dGTP	37 ± 5	100 ± 30	3.7 × 10−1	6↓
dCTP	0.203 ± 0.006	500 ± 40	4.1 × 10−4	1	1.1 × 10−3
dATP	0.013 ± 0.002	800 ± 300	1.6 × 10−5	70 ↓	4.4 × 10−5
dTTP	0.0096 ± 0.0005	1400 ± 100	6.9 × 10−6	120 ↓	1.9 × 10−5
21-19/50mer (10-nucleotide gap)
dGTP	10.5 ± 0.6	780 ± 90	1.3 × 10−2	160 ↓
dCTP	0.0023 ± 0.0001	580 ± 60	4.0 × 10−6	110 ↓	2.9 × 10−4
dATP	0.00166 ± 0.00009	440 ± 60	3.8 × 10−6	300 ↓	2.8 × 10−4
dTTP	0.00090 ± 0.00006	620 ± 90	1.5 × 10−6	560 ↓	1.1 × 10−4
21/41mer (no gap)
dGTP	31.4 ± 0.6	48 ± 2	6.5 × 10−1	3 ↓
dCTP	0.024 ± 0.001	230 ± 30	1.0 × 10−4	4 ↓	1.6 × 10−4
dATP	0.111 ± 0.007	650 ± 90	1.7 × 10−4	7 ↓	2.6 × 10−4
dTTP	0.094 ± 0.005	1100 ± 100	8.5 × 10−5	10 ↓	1.3 × 10−4

^aA downward-pointing arrow (↓) indicates the ratio was calculated as (k_p/K_d)_{1-nucleotide gap}/(k_p/K_d)_{≥2-nucleotide gap}.

^bCalculated as (k_p/K_d)_incorrect/[(k_p/K_d)_correct + (k_p/K_d)_incorrect].