Table 1.
The reductive half-reaction of NQO1 P187S is compromised, thereby affecting its ability to accept electrons from NAD(P)H. Bimolecular rate constants (m−1·s−1) were determined for NQO1 proteins with NADH or NADPH as reducing agent. The absorption change of protein-bound FAD at 445 nm was monitored in a stopped-flow instrument at 4 °C.
| Protein | NADH kred (m−1·s−1) | NADPH kred (m−1·s−1) |
|---|---|---|
| NQO1 | (3.5 × 106) ± (1.0 × 106) | (5.7 × 106) ± (2.7 × 106) |
| NQO1 P187S | (1.2 × 104) ± (1.7 × 103) | (8.5 × 104) ± (1.8 × 106) |
| NQO1 Δ50 | (4.7 × 103) ± (0.7 × 103) | (1.3 × 104) ± (0.1 × 104) |
| NQO1 P187S Δ50 | (3.2 × 103) ± (0.2 × 103) | (8.2 × 104) ± (0.2 × 104) |