Table 2.

L-Leucine Inhibition Parameters for MtIPMS and Mutant Enzymes^a

Enzyme	Ki(µM)	Ki* (µM)	β
WT	12 ± 3	2.3 ± 0.2	0.1
Y169F	18 ± 2	1.6 ± 0.1	-b
E218A	139 ± 42	15 ± 1	0.61/0.16c
H379A	19 ± 4	2.3 ± 0.2	0.24
Y410F	-d	-	-

^aPerformed as described in Materials and Methods.

^bData for Y169F IPMS was fit to equation 5 with β = 0.

^cLimiting values for v_i and v_ss, respectively.

^dInhibition not observed.