Table 1.

The kinetic parameters of the adenylosuccinate lyase enzymes in the direction of AMP formationa

Enzyme	Vmaxb (μmole/min/mg)	KM (μM)	kcat (s−1)	kcat/KM (s−1M−1)
WT	1.56 ± 0.190	3.46 ± 0.44	1.30 ± 0.160	3.75 × 105
M10L	1.90 ± 0.129	3.80 ± 1.14	1.59 ± 0.108	4.18 × 105
I123R	1.24 ± 0.051	2.18 ± 0.46	1.04 ± 0.042	4.76 × 105
I123W	0.55 ± 0.021	3.34 ± 0.80	0.46 ± 0.018	1.38 × 105
T367R	1.01 ± 0.036	1.63 ± 0.36	0.85 ± 0.031	5.19 × 105
T367S	0.96 ± 0.032	1.56 ± 0.33	0.80 ± 0.042	5.14 × 105

^a Activity assays for adenylosuccinate were carried out spectrophotometrically at 282 nm in 50 mM HEPES, pH 7.0 at 25°C. The calculated standard deviation for each parameter is shown.

^bV_max is defined as μmole substrate converted/min/mg enzyme.