TABLE 4.
Kinetic parameters of purified DKGRsb
| Form | Parameters
|
|||
|---|---|---|---|---|
| Km for DKGa (μM) | kcat (s−1) | kcat/Km (mM−1 s−1) | Km for NADPH (μM) | |
| A | 13,500 | 4 | 0.3 | 13 |
| B | 2,000 | 39 | 19 | 10 |
| C | 57 | 31 | 550 | 3.0 |
| D | 67 | 27 | 400 | 2.7 |
a
DKG, 2,5-diketo-d-gluconic acid.
b
Values for forms A and B are from Sonoyama and Kobayashi (35). For forms C and D, kinetic parameters for 2,5-diketo-d-gluconic acid were determined in the presence of 0.15 mM NADPH, and values for NADPH were determined in the presence of 1 mM 2,5-diketo-d-gluconic acid.