Inversion of allosteric effect of arginine on N-acetylglutamate synthase, a molecular marker for evolution of tetrapods

Table 2 Effects of L-arginine on synthase and kinase activities of the arginine resistant and wild-type XcNAGS-K.

	Synthase Activity (μmol min^-1mg^-1)		Kinase Activity (μmol min^-1mg^-1)
XcNAGS-K		+1 mM Arginine		+1 mM Arginine
Wild-type	71.00 ± 1.07^a	nd^b	61.93 ± 0.83	7.52 ± 1.26
F35C	9.66 ± 0.25	4.31 ± 0.01	65.14 ± 4.77	44.35 ± 2.70
E280A	26.93 ± 0.68	26.68 ± 0.50	82.13 ± 1.79	82.44 ± 0.16
G286P	3.51 ± 0.04	3.39 ± 0.08	76.57 ± 3.97	50.70 ± 7.43
G288S	46.04 ± 1.09	42.55 ± 1.02	55.62 ± 1.26	42.92 ± 5.42

^aActivities are averages of three measurements and their associated standard errors
^bNot detectable.

ISSN: 1471-2091