Table 1.

Kinetic parameters for ^TmaACT-^PfuDAH7PS, PfuDAH7PS, and TmaDAH7PS

Enzyme	KmPEP (µM)	KmE4P (µM)	kcat (s−1)	kcat/KmE4P (s−1⋅µM−1)
TmaACT-PfuDAH7PS	46 ± 4	10 ± 1	2.41 ± 0.02	0.24
PfuDAH7PS*	120 ± 10	22 ± 2	9.70 ± 0.03	0.44
TmaDAH7PS	4.85 ± 0.04	13 ± 1	11.7 ± 0.2	0.9
TmaACT-PfuDAH7PS (with Tyr)†	42 ± 2	20 ± 2	1.6 ± 0.1	0.08
TmaDAH7PS (with Tyr)b	21 ± 1	118 ± 10	2.59 ± 0.07	0.02

*The kinetic parameters for PfuDAH7PS determined in the absence and presence of Tyr are identical.

^†Tyr concentrations were 500 µM for ^TmaACT-^PfuDAH7PS and 150 µM for TmaDAH7PS. Values for TmaDAH7PS are from ref. (27). The activity of ^TmaACT-^PfuDAH7PS is reduced by 66 ± 2% and of TmaDAH7PS by 13 ± 2% at these concentrations (see Fig. 2).