Table 2.
Summary of WT and mutant UGDH kinetic constants.
| Km (µM) | Vmax (nmol/min/mg) | |
|---|---|---|
| UDP-glucose | ||
| WT | 28.6 ± 6.8 | 235.6 ± 12.5 |
| A44V | 15.9 ± 2.3* | 118.3 ± 3.3*** |
| A82T | ND | ND |
| NAD+ | ||
| WT | 401 ± 75 | 219.2 ± 11.2 |
| A44V | 316 ± 54 NS | 109.4 ± 4.5*** |
| A82T | ND | ND |
Steady state rate constants for UGDHWT and UGDHA44V were determined by varying UDP-glucose or NAD+ independently and fitting to the Michaelis–Menten equation. UGDHA82T steady state constants could not be determined. Values indicate mean ± SD of triplicate assays. Asterisks indicate p-values of p < 0.05(*) and p < 0.001(***), NS: non-significant (p > 0.05) as determined by Student t-test. ND: not determined.