TABLE 3.

Effect of increasing E-XMP* on MPA inhibition

Conditions were as follows: AnImdA, 500 μm IMP and 500 μm NAD⁺; and PbIMPDH-A and PbIMPDH-B, 3 mm IMP and 1 mm NAD.

Enzyme	Total E-XMP*	IC50(D2O)a	D2OIC50b	IC50(APAD+)a	AIC50c	IC50(D2O + APAD+)a	(D2O+A)IC50d
	%	nm		nm		nm
AnImdA	NDe	21 ± 3	1.2 ± 0.2	13 ± 1	2.0 ± 0.2	15 ± 2	1.7 ± 0.3
PbIMPDH-A	20 ± 1	75 ± 10	5.7 ± 0.9	97 ± 5	4.4 ± 0.4	45 ± 3	9.4 ± 0.7
PbIMPDH-B	7 ± 3	(1.2 ± 0.1) × 104	2.2 ± 0.8	(1.0 ± 0.1) × 104	2.7 ± 0.9	3400 ± 200	8.0 ± 2.6

^a Parentheses indicate the substitutions of D₂O for H₂O and/or APAD⁺ for NAD⁺.

^b The ratio of IC₅₀ to IC₅₀(D₂O).

^c The ratio of IC₅₀ to IC₅₀(APAD⁺).

^d The ratio of IC₅₀ to IC₅₀(D₂O+APAD⁺).

^e ND, no data.