Table 4.

K_i Values of Nicotinamidase Inhibitors (µM)

Substrate	BbNica	PfNicb	Pnc1c	SpNicd	CePNC1e	CePNC2f
16 g	0.11± 0.02	0.034± 0.007	1.4± 0.1	0.011± 0.001	0.11± 0.01	0.022± 0.004
17 g	1.3± 0.20	0.59±0.14	4.0± 0.80	0.071± 0.022	0.14± 0.02	0.088± 0.02
18 g	0.85± 0.04	0.039± 0.004	3.8± 0.54	0.14± 0.02	0.31± 0.05	0.14± 0.02
19 g	0.19± 0.03	0.023± 0.005	0.65± 0.07	0.056± 0.002	NDh	ND
20	370i	NIj	5000i	110i	ND	ND
21	18i	4.9i	NI	0.73± 0.29g	ND	ND
22	153i	1.0± 0.11	68i	50i	5.3± 1.0g	0.44± 0.022g
23	2000i	1000i	85i	500i	ND	ND
24	342i	10i	46i	60i	ND	ND
25	NI	NI	NI	NI	ND	ND
nicotinic acid	NI	NI	NI	2000i	NI	NI

Typical enzyme concentrations: ^a[BbNic] = 140 nM.

^b[PfNic] = 14 nM.

^c[Pnc1] = 210 nM.

^d[SpNic] = 12 nM.

^e[CePNC1] = 10 nM.

^f[CePNC2] = 133 nM. In most cases the inhibitions were determined by the GDH assay as described in Materials and Methods.

^gThe inhibition data was fit to Morrison’s equation 2 described in the Materials and Methods (See examples of data and fits in Figure 6 and in the Supporting Information). The determined K_i^app values were converted to the K_i values (the intrinsic binding constant of the inhibitor for the enzyme) shown in Table 4 by Equation 3 in the Materials and Methods.

^hND= not determined.

ⁱThe inhibition data were fit to Equation 1 as described in Materials and Methods.

^jNI = no inhibition detected.