. Author manuscript; available in PMC: 2010 Mar 10.

Published in final edited form as: Biochemistry. 2009 Mar 10;48(9):1996–2004. doi: 10.1021/bi801707t

Table 1.

Steady-State Kinetic Parameters for MtIPMS and Mutant Enzymes^a

	α-KIV^b				Acetyl-CoA^b

Enzyme	k_cat1^c (min⁻¹)	K₁^c (µM)	k_cat2^c (min⁻¹)	K₂^c (µM)	k_cat1 (min⁻¹)	K₁ (µM)	k_cat2 (min⁻¹)	K₂ (µM)

WT	152 ± 3	7.1 ± 0.5	-	-	163 ± 3	24 ± 2	-	-
Y169F	285 ± 16	13.4 ± 2.6	-	-	340 ± 13	40 ± 6	-	-
E218A	2.2 ± 0.1	1.6 ± 0.2	1.3 ± 0.1	39± 11	3.5 ± 0.2	9.5 ± 1.1	5.6 ± 2.8	697 ± 615
H379A	42 ± 18	1.6 ± 1.1	89 ± 17	19 ± 6	153 ± 2	23 ± 1.5	-	-
Y410F	4.5 ± 0.2	0.5 ± 0.1	-	-	5.6 ± 0.2	1.1 ± 0.2	-	-

All reactions were performed as described in Materials and Methods.

Varied substrate

For enzymes displaying substrate activation, kinetic parameters with subscripts 1 and 2 represent the kinetic parameters for the unactivated and activated forms of the enzyme, respectively. For enzymes without substrate activation, k_cat1 and K₁ are k_cat and K_m, respectively.