Table 4.

The predicted binding free energies and distances facilitating the H-transfer for AAI, 3-NBA and their reduced metabolites to human NQO1. The data is taken from previous studies [52,69,73].

Compound	NQO1 FADH− Deprotonated (Anionic Form)		NQO1 Enol-FADH2 (Protonated Form)
	direct H-transfer		direct H-transfer		mediated H-transfer (e−,H+,e−)
	Estimated Free Energy of binding [kcal/mol]	N5(FAD)-O(NBA/AAI) distance [Å] a	Estimated Free Energy of binding [kcal/mol]	N5(FAD)-O(NBA/AAI) distance [Å] a	Estimated Free Energy of binding [kcal/mol]	OH(Y128)-O(NBA/AAI) distance [Å] b
3-NBA	−5.7	3.7	−5.7	3.5	−6.2	3.1
AAI	−6.4	3.2	−6.3	3.2	−7.9	2.8

^a, Distance between the oxygen in nitro group of AAI and that in nitro group of 3-NBA and nitrogen 5 of reduced FAD, see Figure 4 and Figure 5; ^b, Distance between the oxygen in nitro group of AAI and in group of 3-NBA and OH group of Tyr128, see Figure 4 and Figure 5.