A mathematical model for the adenylosuccinate synthetase reaction involved in purine biosynthesis

Table 1 Kinetic parameters of Escherichia coli adenylosuccinate synthetase. Our model output, and data provided from the literature.

Parameter	Model output	Literature data	Reference
Km _GTP	0.023 mM	0.01 mM	7
		0.048 mM	6
		0.0221 mM	10
		0.0262 ± 0.0023 mM	12
Km _IMP	0.02 mM	0.02 mM	7
		0.054 mM	6
		0.0243 mM	10
		0.0278 ± 0.0013 mM	12
Km _ASP	0.3 mM	0.35 mM	7
		0.225 ± 0.016 mM	9
		0.27 mM	6
		0.191 mM	10
		0.23 ± 0.04 mM	12
Ki_SUCC*	8 mM	-	-
Ki _GDP	0.008 mM	0.022 mM	6
Ki _ASUC	0.0075 mM	0.27 mM (for IMP)**	6
		0.47 mM (for ASP)	6
Km _Mg	0.08 mM	0.114 ± 0.026 mM	9
Ki _GMP	0.024 mM	0.092 mM (for GTP)	6
		0.074 mM (for IMP)	6
Ki _AMP	0.01 mM	0.095 mM	6

* The effect of SUCC was examined by Rudolph and Fromm [7]. However, their formula is too complicated (it describes the effect of one inhibitor using four different constants) and the inhibition constants were not evaluated.
** In 1963 Wyngaarden and Greenland [6] proposed that ASUC is a competitive inhibitor of both IMP and ASP, and GMP is a competitive inhibitor of both IMP and GTP.

ISSN: 1742-4682