Table 2.

Inhibition of the GTPase activity by nucleotide analogs

Molecule	IC50 (μM)	Ki (μM)	Phosphohydrolase specific activity (Percentage of GTP)a	Inhibitory potentialb
GTP	87	16	100	1.0
dGTP	76	14	99	1.1
A-3	83	15	88	1.2
A-4	8.1	1.5	18	60
A-5	150	27	17	3.4
A-6	53	9.6	70	2.4
A-8	10	1.8	10	86
A-9	16	2.9	41	13
A-10	93	17	20	4.7
A-11	2.0	0.4	16	268
A-12	6.1	1.1	138	10
A-13	32	5.9	109	2.5
A-15	49	8.8	111	1.6
A-17	59	11	116	1.3
A-18	8.1	1.5	12	89
A-19	61	11	38	3.8
A-20	2.0	0.4	7.2	597
A-22	113	21	81	0.9
A-24	8.1	1.5	7.2	149
Tripoly-PO4	0.4	0.1	3.6	5965

^aThe phosphohydrolase specific activities were calculated from the slopes of the titration curves and normalized to the specific activity for the hydrolysis of GTP.

^bThe inhibitory potential is defined by the following equation:

(K_iGTP/K_iMolecule) × (Spec. activity_GTP/Spec. activity_Molecule)