TABLE 5.

Catalytic activities of site-directed mutants of full-length RePC compared to wild-type for the oxamate-induced decarboxylation of oxaloacetate

Reaction conditions were as follows: 100 mm Tris-HCl (pH 7.8), 30 °C, 0.2 and 1 mm oxaloacetate, 0.5 mm oxamate, 0.25 mm acetyl-CoA.

	1 mm oxaloacetate, kcata	0.2 mm oxaloacetate, kcat	0.2 mm oxaloacetate + 0.5 mm oxamate
			kcat	kcat (+oxamate)/kcat (−oxamate)
	min−1	min−1	min−1
Wild type	1.23 ± 0.006	1.29 ± 0.02	3.81 ± 0.2	3.0
Y628F	0.97 ± 0.05	0.87 ± 0.006	0.99 ± 0.03	1.1
Y628A	0.79 ± 0.04	0.50 ± 0.01	0.49 ± 0	1.0
D590A	0.92 ± 0.02	0.85 ± 0.006	0.91 ± 0.02	1.1

^a Specific activities were determined in triplicate, and the error reported is the S.D. value of the three determinations.