Table 5. Intrinsic Binding Energy of Ligands for the Dinucleotide Site^a.

		NAD+ (mM)		β-Me-TAD (μM)		Tz (mM)		ADP (mM)
enzyme	Kc	Kii	Kintr	Ki	Kintr	Ki	Kintr	Ki	Kintr
TfIMPDHb	140	6.8 ± 1.8	0.07	2.3 ± 0.4	0.02	50 ± 10	0.3	31 ± 2	0.2
CpIMPDHc	4	4.9 ± 0.5	0.30	0.6 ± 0.04	0.1	1.5 ± 0.1	0.3	42 ± 6	8
hIMPDH2d	≤0.2	0.59 ± 0.02	0.59	0.06 ± 0.02	0.06	1.3 ± 0.1	1.3	8.8 ± 2.2	8.8

^aThe intrinsic binding constant for NAD⁺ is derived from the global fits. The intrinsic binding constants for β-Me-TAD, tiazofurin (Tz), and ADP are calculated from K_intr = K_i (1/(1 + K_c)).

^bSee refs 14 and 23.

^cSee ref 16.

^dSee ref 24. The intrinsic binding constant for NAD⁺ is derived from the global fits.