TABLE 4.
Kinetic parameters of AEH
| Substratea | Mean ± SE of:
|
||
|---|---|---|---|
| Km (mM) | kcat (s−1) | kcat/Km (s−1 · mM−1) | |
| NIPGBb | 1.1 ± 0.5 | 0.4 ± 0.07 | 0.4 ± 0.2 |
| Cephalexin | 0.34 ± 0.03 | 347 ± 10 | 1021 ± 95 |
| Ampicillinb | 1.0 ± 0.6 | 162 ± 61 | 162 ± 115 |
| D-PGM | 7 ± 2 | 1035 ± 123 | 148 ± 46 |
| D-PGA | >13 | >43 | 3.3c |
| Cefadroxild | 1.7 ± 0.3 | 9.6 ± 0.4 | 6 ± 1 |
| Amoxicillind | 2.6 ± 0.2 | 10 ± 0.3 | 3.9 ± 0.3 |
| HPGM | 11 ± 3 | 263 ± 30 | 24 ± 7 |
a
For glutaryl 7-ACA and adipoyl 7-ADCA the hydrolysis was less than 300 nmol · s−1 · mg−1 of AEH at 25 mM substrate.
b
Substrate inhibition was observed with Ki of 200 mM (NIPGB) and Ki of 3 mM (ampicillin).
c
Calculated from the initial slope of the Michaelis-Menten curve; the error is 30%.
d
Data were measured using His-tagged protein with the same catalytic properties as the wild type (unpublished data).