TABLE 5.
Results of inhibition studies for purified AKI, AKII, and AKIII proteins
| Enzyme | AK activity in the presence of inhibitors (%)a
|
IC50c
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
| None | Ile | Met | Thr | Lys | meso-DAP | Lys + Thrb | Inhibitor | Concn (mM) | |
| AKI | 100 | 115 | 95 | 95 | 110 | 15 | 95 | DAP | 0.1 |
| AKII | 100 | 105 | 90 | 105 | 5 | 95 | 4 | Lys | 0.3 |
| AKIII | 100 | 130 | 125 | 35 | 50 | 150 | 0.8 | Thr | 4 |
| AKIII | Lys | 5 | |||||||
a
The values are the percentages of remaining AK activity; 100% activity was defined as the activity of the AK protein obtained without any inhibitor compound. The AK assays were performed in the presence of the various inhibitor compounds at a concentration of 5 mM. Ile, l-isoleucine; Met, l-methionine; Thr, l-threonine; Lys, l-lysine.
b
The concentration of each compound was 5 mM.
c
The IC50 values were determined when significant inhibition was observed, as follows: for AKI, with various meso-DAP concentrations; for AKII, with various Lys concentrations; and for AKIII, with various Thr and Lys concentrations (see Materials and Methods).