Table 4. Tabulated Steady-State Kinetic Parameters for RpNiR, the RpNiR-Core Protein, and AxNiR^a.

CuNiR construct	kcat per monomer (s–1)	Km (mM)	Ki (mM)	kcat/Km (mM–1 s–1)
WT RpNiR	1.1 ± 0.03	1.6 × 10–3 ± 0.2 × 10–3	n/a	6.9 × 102 ± 0.9 × 102
WT Ax NiR	202.7 ± 0.7	2.1 × 10–2 ± 0.2 × 10–2	n/a	9.3 × 103 ± 0.9 × 103
RpNiR-core	2.3 ± 0.2	4.1 × 10–1 ± 1.6 × 10–1	1.3 × 102 ± 0.8 × 102	5.6 ± 2.1
Y323F RpNiR-core	2.6 ± 0.2	2.9 × 10–1 ± 0.8 × 10–1	1.6 × 102 ± 0.7 × 102	8.8 ± 2.5

^aData are shown ± error of fit.