Table 3.

The SAICAR and adenylosuccinate activities of the altered enzymes and wild typea

Enzyme	SAMP activity μmole/min/mg	SAICAR activity μmole/min/mg	SAICAR/SAMP
WT	1.56	1.94	1.27
M10L	1.90	1.72	0.91
I123R	1.24	1.14	0.92
I123W	0.55	0.50	0.91
T367R	1.01	1.00	0.99
T367S	0.96	0.95	0.99

^a All activities were determined under standard conditions, at pH 7.0, in the presence of either 90 μM adenylosuccinate or SAICAR. The data presented represents an average of at least three activity determinations.