Table 3. Apparent Michaelis–Menten constants for dihydropyrimidinase using the substrate of each enzyme in the cyclic amidohydrolase family.
| Dihydropyrimidinase | ||||
|---|---|---|---|---|
| Substrate | V max | K m | V max/K m | Fold |
| Dihydrouracil | 7.6 ± 0.4 | 0.7 ± 0.1 | 10.9 | 1.0 |
| Phthalimide | 2.7 ± 0.6 | 1.0 ± 0.3 | 2.7 | 0.25 |
| 5-Propyl-hydantoin | 1.2 ± 0.1 | 8.1 ± 1.5 | 0.15 | 0.01 |
| Allantoin | Not hydrolyzed | |||
| Dihydroorotate | Not hydrolyzed | |||
The kinetic parameters Km and Vmax were determined by fitting the hydrolyzing rate from individual experiments to the Michaelis–Menten equation, and then the standard errors were given.