Table 2. Extracted Parameters from Kinetic and Thermodynamic Studies^a.

	ΔHT0⧧ (kJ mol–1)	ΔST0⧧ (J mol–1 K–1)	ΔCp⧧(kJ mol–1 K–1)	ΔHT0⧧ (kJ mol–1)	ΔST0⧧ (J mol–1 K–1)	ΔCp⧧(kJ mol–1 K–1)
	NADPH			NADH
WT	30.4 ± 0.3	–113.9 ± 0.9	–0.50 ± 0.05	35.4 ± 0.1	–120.5 ± 0.5	0.39 ± 0.03
L25A	23.3 ± 1.2	–133.7 ± 4.1	–0.92 ± 0.12	33.6 ± 0.5	–122.1 ± 1.7	0.28 ± 0.05
L25I	30.4 ± 0.6	–114.9 ± 2.0	–0.43 ± 0.07	42.7 ± 1.7	–97.7 ± 6.0	0.32 ± 0.18
I107A	17.8 ± 2.3	–160.2 ± 7.7	–1.08 ± 0.23	46.4 ± 1.1	–83.8 ± 3.6	–0.47 ± 0.22
I107L	31.5 ± 0.7	–111.6 ± 2.4	–0.44 ± 0.08	38.7 ± 0.2	–110.0 ± 0.8	0.23 ± 0.04
	(R)-[4-2H]-NADPH			(R)-[4-2H]-NADH
WT	36.8 ± 0.3	–108.0 ± 0.1	–0.32 ± 0.04	40.3 ± 0.1	–120.4 ± 0.5	0.46 ± 0.02
L25A	31.9 ± 1.1	–120.5 ± 3.7	–0.78 ± 0.15	40.3 ± 1.1	–115.7 ± 3.8	0.42 ± 0.14
L25I	36.7 ± 0.5	–109.5 ± 1.6	–0.53 ± 0.09	44.9 ± 0.2	–106.8 ± 0.8	0.30 ± 0.07
I107A	19.0 ± 0.2	–172.6 ± 0.7	–1.43 ± 0.02	53.5 ± 1.7	–77.0 ± 5.6	0.17 ± 0.22
I107L	35.7 ± 0.4	–112.9 ± 1.4	–0.65 ± 0.07	45.4 ± 0.3	–103.9 ± 0.9	0.43 ± 0.07
	Isotope Effect: (R)-[4-2H]-NADPH–NADPH			Isotope Effect: (R)-[4-2H]-NADH–NADH
WT	6.4 ± 0.4	5.8 ± 1.5	0.18 ± 0.06	4.9 ± 0.2	0.1 ± 0.7	0.07 ± 0.04
L25A	8.6 ± 1.27	13.3 ± 5.6	0.14 ± 0.19	6.6 ± 1.2	6.4 ± 4.2	0.13 ± 0.15
L25I	6.3 ± 0.7	5.4 ± 2.5	–0.11 ± 0.11	2.3 ± 1.8	–9.2 ± 6.0	–0.03 ± 0.19
I107A	1.2 ± 2.3	–12.3 ± 7.7	–0.35 ± 0.23	7.1 ± 2.0	6.8 ± 6.7	0.64 ± 0.31
I107L	4.2 ± 0.8	–1.3 ± 2.8	–0.22 ± 0.11	6.7 ± 0.4	6.1 ± 1.2	0.19 ± 0.08

^aApparent activation parameters were obtained by fitting the data in Figure 4 to eq 1 with T₀ = 298 K. The isotope effects are the differences in activation parameters (e.g., ΔH_T0^⧧,D – ΔH_T0^⧧,H).