Table 1.
Experimental and intrinsic KIEs of TcdA-GTD and TcdB-GTD glucohydrolase reaction.
| Label | Type of KIE | Experimental KIE TcdB-GTD | Intrinsic KIE TcdB-GTD | Intrinsic KIE TcdA-GTD |
|---|---|---|---|---|
| 1ʺ-3H | α-secondary | 1.203 ± 0.001 | 1.216 ± 0.001 | 1.261 ± 0.002 |
| 1ʺ-14C | Primary label | 1.042 ± 0.001 | 1.045 ± 0.001 | 1.029 ± 0.001 |
| 1ʺ-18O | Primary leaving group | 1.026 ± 0.002 | 1.027 ± 0.002 | 1.049 ± 0.002 |
| 2ʺ-3H | β-secondary | 1.012 ± 0.001 | 1.014 ± 0.001 | 1.052 ± 0.005 |
| 6ʺ-3H | Remote label | 1.053 ± 0.001 | 1.056 ± 0.001 | 1.065 ± 0.003 |
| 6ʺ-14C | Remote label | 1.000 | 1.000 | 1.000 |
Positions of isotopic labels in the substrate UDP-glucose designed for multiple KIE measurement and the resulting experimental KIEs.
Six independent measurements were performed for each KIE and the data represent the mean values ± SEM.
Experimental KIEs were corrected for forward commitment using Eq. 5 to give intrinsic KIE values.
The 6′′-14C value of unity provides the standard unity reference for all other isotope effects.
Source Data are provided as a Source Data file.