Table 3.

Summary of steady-state kinetic constants

			WT 2Ca		NΔ39 2Ca
Substrate	[ssRNA-1] (μM)	Assay	K M (mM)	k cat (min−1)	K M (mM)	k cat (min−1)
ATP	5	Radioactiveb	0.86 ± 0.2 [0.4–1.3]	70 ± 4 [63–78]	1.0 ± 0.3 [0.2–1.7]	18 ± 1 [16–21]
ATP	0	Radioactiveb	1.8 ± 0.2 [1.4–2.1]	8.6 ± 0.2 [8.1–9.1]	1.9 ± 1.2 [-0.6–4.5]	3.2 ± 0.6 [2.1–4.5]
3′-dATP	5	Colorimetricc	0.70 ± 0.1 [0.5–0.9]	27 ± 0.7 [25–29]	3.5 ± 0.9 [1.5–5.4]	19 ± 2 [15–24]

^aThe K_M and k_cat are presented ± standard error with 95% confidence interval provided in brackets below.

^bData from Figure 8.

^cData from Figure 9.