Table 1.

Effect of Identified Inhibitors on Substrate-Dependent Spa47 Enzyme Kinetics^a

Inhibitor	Concentration	KMb (μM)	Vmax (μM s−1)	kcatc (s−1)	kcat/KM (M−1 s−1)
8573
	0 μM	52 ± 30	0.08 ± 0.01	1.5 ± 0.2	(3.0 ± 1.8) × 104
	50 μM	52 ± 37	0.06 ± 0.01	1.1 ± 0.2	(2.1 ± 1.5) × 104
	225 μM	23 ± 24	0.02 ± 0.01	0.4 ± 0.1	(1.6 ± 1.7) × 104
	500 μM	44 ± 20	0.02 ± 0.00	0.4 ± 0.1	(1.0 ± 0.5) × 104
3812
	0 μM	59 ± 31	0.06 ± 0.01	1.2 ± 0.2	(2.0 ± 1.1) × 104
	50 μM	58 ± 33	0.05 ± 0.01	0.9 ± 0.1	(1.6 ± 0.9) × 104
	225 μM	88 ± 41	0.05 ± 0.01	0.9 ± 0.1	(1.1 ± 0.5) × 104
	500 μM	73 ± 36	0.04 ± 0.01	0.8 ± 0.1	(1.0 ± 0.5) × 104
6573
	0 μM	89 ± 40	0.06 ± 0.01	1.3 ± 0.2	(1.4 ± 0.7) × 104
	50 μM	69 ± 39	0.06 ± 0.01	1.1 ± 0.2	(1.6 ± 0.9) × 104
	225 μM	109 ± 79	0.03 ± 0.01	0.6 ± 0.1	(0.6 ± 0.4) × 104
	500 μM	63 ± 46	0.02 ± 0.00	0.4 ± 0.1	(0.6 ± 0.4) × 104
8771
	0 μM	50 ± 40	0.07 ± 0.02	1.4 ± 0.3	(2.7 ± 2.2) × 104
	50 μM	56 ± 34	0.07 ± 0.01	1.3 ± 0.2	(2.4 ± 1.5) × 104
	225 μM	81 ± 36	0.05 ± 0.01	0.9 ± 0.1	(1.1 ± 0.5) × 104
	500 μM	108 ± 107	0.03 ± 0.01	0.5 ± 0.1	(0.5 ± 0.5) × 104

^aInitial Spa47 reaction velocities were measured as a function of substrate (ATP) and inhibitor concentration.

^bApparent K_M and V_max values ± the standard error were determined by fitting the mean values from three independent experiments to the Michaelis–Menten equation.

^cApparent k_cat and k_cat/K_M values ± the standard error were calculated using the apparent K_M and V_max values in the table.