Table 2.
Kinetic properties of the wild-type human arginase type I and chimeric species of loop A.
| Arginine | Agmatine | |||||
|---|---|---|---|---|---|---|
| Km (mM) | kcat (s−1) | kcat/Km (M−1s−1) | Km (mM) | kcat (s−1) | kcat/Km (M−1s−1) | |
| WT-arginase | 1.5 ± 0.5 | 190 ± 10 | 1.3 × 105 | n/a | ||
| E. coli agmatinase | n/a | 1.1 ± 0.2 | 120 ± 10 | 1.1 × 105 | ||
| Chimera A1 I129T/N130Y/T131A |
2.5 ± 0.5 | 6.2 ± 0.4 | 2.4 × 103 | n/a | ||
| Chimera A2 I129T/N130Y/T131A+∆ P132-T134 |
n/a | 6 ± 1 | 1.1 ± 0.2 | 1.8 × 102 | ||
| Chimera A3 I129T/N130Y/T131A ∆ P132–T134/N139F/L140D |
n/a | n/a | ||||
| Chimera A4 I129T/N130Y/T131A/∆ P132–T134/T135N/T136G/S137C/G138E/N139F/L140D |
n/a | n/a | ||||
| Chimera A5 (residues I129 t P144 according to Loop A in agmatinase) | n/a | n/a | ||||
The values of the kinetic parameters indicated in this table correspond to the results of two experiments performed in duplicate and the standard deviations were not greater than 5%. n/a: indicates no activity with the respective substrate.