Table 4. ITC-derived thermodynamic parameters.

	Kd(μM)	ΔG (kcal mol−1)	ΔH (kcal mol−1)	−TΔS (kcal mol−1)
IMPDH	1.7	−7.9	−26.4	18.5
IMPDH + GTP	26	−6.3	−55.0	48.7
IMPDH + GDP	63	−5.7	−30.9	25.2

GDP, guanosine-5′-diphosphate; GTP, guanosine-5′-triphosphate; IMP, Inosine-5′-monophosphate; IMPDH, IMP dehydrogenase; ITC, isothermal titration calorimetry.

IMP titration of different AgIMPDH wild-type protein in the presence or absence of 5 mM GTP or GDP. Estimated relative error in K_d is 15–20%, absolute error for ΔG is ∼0.1 kcal mol⁻¹ and the absolute error for ΔH and –TΔS is 0.3–0.5 kcal mol⁻¹.