Table 3.
Biochemical properties of WT and mutant protein α
| Proteins | CTP reductase activity, nmol/min/mg* | EPR Gly radical† | Methionine, mol/mol α† |
|---|---|---|---|
| WT | 280 | + | 0.95 |
| C644A | <1 | ND | 0.03 |
| C647A | 5.5 | ND | 0.07 |
| C662A | <1 | ND | 0.04 |
| C665A | <1 | ND | 0.10 |
ND, not detectable.
*
Two to 4 μg of each protein was assayed for CTP reduction under standard conditions.
†
Under standard activation conditions and after a 1-h reaction, the same enzyme solution was used both for glycyl radical determination by EPR spectroscopy and for methionine quantification.