TABLE 1.

Pre-steady-state kinetic parameters for dCTP incorporation opposite G by pol ι(1–445), pol ι(26–445), and R96G pol ι(1–445) in the presence of either Mg²⁺ or Mn²⁺

Metal	pol	kpol	Kd,dCTP	kpol/Kd,dCTP	Relative efficiencya
		s−1	μm	m−1 s−1
MgCl2 (2 mm)	pol ι (1–445)	0.43 ± 0.02	670 ± 100	6.4 × 102	1
	pol ι (26–445)	0.77 ± 0.024	390 ± 40	2.0 × 103	3.1
	R96G pol ι (1–445)	0.063 ± 0.007	5200 ± 1300	1.2 × 10	0.019
MnCl2 (150 μm)	pol ι (1–445)	0.74 ± 0.06	1.5 ± 0.4	4.9 × 105	1
	pol ι (26–445)	0.79 ± 0.03	1.8 ± 0.2	4.4 × 105	0.90
	R96G pol ι (1–445)	0.077 ± 0.002	1.4 ± 0.1	5.5 × 104	0.11

^a Relative efficiency, calculated as the ratio of the k_pol/K_d,dCTP of each pol ι for dCTP insertion opposite G to the k_pol/K_d,dCTP of pol ι(1–445) for dCTP insertion opposite G.