Table 3.

Kinetic Parameters for Isomerization of GAP by Wildtype and K12G Mutant Yeast Triosephosphate Isomerase.^a

Yeast TIM	kcatb S−1	Kmb mM	kcat/Km M−1 s−1	Ki for PGA mM
Wildtype	7300 ± 400	1.1 ± 0.2	6.6 × 106c	0.019 ± 0.004d
K12G	0.6 ± 0.2	50 ± 20	12 ± 0.4 e	1.1 ± 0.2f
Effect g	1.2 × 104	50	5.5 × 105	60
ΔΔG or ΔΔG‡ kcal/mol	5.6	2.3	7.8	2.4

^aAt pH 7.5 (30 mM TEA), 25 °C and I = 0.10 (NaCl). Quoted errors are standard errors obtained from least squares analysis.

^bDetermined from the fit of initial velocity data to the Michaelis-Menten equation.

^cCalculated as the ratio of the values of k_cat and K_m

^dDetermined by global nonlinear least squares analysis of initial velocity data in the presence of zero, 21 and 130 µM PGA.

^eDetermined as the slope of the plot of v_i/[E] against [GAP] for [GAP] ≤ 3 mM (Figure 4, inset).

^fDetermined from the nonlinear least squares fit of the data in Figure 5 to eq 7.

^gThe effect of the K12G mutation on the kinetic parameter.