Table 2.
pH/pD | D2O | H2O | H2O/D2O ratio |
Vo/e, s−1 | |||
6.0 | 58.9 ± 3 | 175 ± 7 | 3.0 ± 0.3 |
7.0 | 76.2 ± 6 | 338 ± 8 | 4.4 ± 0.4 |
8.0 | 66.2 ± 7 | 261 ± 10.2 | 3.9 ± 0.6 |
All measurements were done in 5 mM potassium phosphate (KH2PO4/K2HPO4) buffer titrated to the appropriate pH/pD, taking into account the following relationship between pH and pD: pD = pHobs + 0.38. Additional details are provided in Materials and Methods. Vo/e, [velocity/(enzyme)].