Table 1. Effect of Mutations of Phosphodianion Gripper Amino Acid Residues on the Kinetic Parameters for OMPDC-Catalyzed Decarboxylation of OMP^a.

OMPDC	I	kcat (s–1)b	Km (M)b	kcat/Km (M–1 s–1)
wild type	0.105	15	1.4 × 10–6	1.1 × 107
Q215Ac	0.105	24 ± 1	(0.94 ± 0.09) × 10–4	2.6 × 105
Y217F	0.105	20 ± 1	(1.1 ± 0.15) × 10–4	1.8 × 105
R235Ad	0.105	1.0	(1.1 ± 0.15) × 10–3	910
Q215A/Y217Fe	0.105	4.8 ± 0.25	(1.4 ± 0.24) × 10–3	3.4 × 103
	0.05	5.0 ± 0.32	(0.29 ± 0.04) × 10–3	1.7 × 104
Q215A/R235Af	0.105	0.020 ± 0.02	(1.4 ± 0.1) × 10–3	14
	0.05	0.019 ± 0.05	(3.5 ± 0.3) × 10–4	54
Y217F/R235Ag	0.105	0.11 ± 0.016	(27.1 ± 4.4) × 10–3	4.1
	0.075	0.11 ± 0.016	(12.9 ± 2.1) × 10–3	8.5
	0.05	0.11 ± 0.016	(6.1 ± 1.1) × 10–3	18
triple mutanth	0.105	(4.8 ± 0.8) × 10–4	(12.9 ± 2.4) × 10–3	0.037
	0.05	(4.8 ± 0.8) × 10–4	(2.2 ± 0.5) × 10–3	0.22

^aFor reactions at pH 7.1 (30 mM MOPS), 25 °C, and constant ionic strength (NaCl).

^bThe quoted errors are the standard deviations obtained from the nonlinear least-squares fits of data from Figures 3 and 4 to the Michaelis–Menten equation.

^cData from ref (33).

^dData from ref (34).

^eData from Figure 3A.

^fData from Figure 3B.

^gData from Figure 4A.

^hData from Figure 4B.