Table S3.
Kinetics of the urea-induced conversion of the blue state (λmax = 625 nm) to the red state (λmax = 650 nm) of PCB-ApcEΔΔ
| Curea | Monitor, nm | τ1, s | A1, % | τ2, s | A2, % | R2 |
| 1 M | 616 | 190.1 (−) | 100.0 | — | — | 0.9962 |
| 658 | 195.7 (+) | 100.0 | — | — | 0.9980 | |
| 2 M | 616 | 111.1 (−) | 100.0 | — | — | 0.9939 |
| 658 | 132.3 (+) | 100.0 | — | — | 0.9929 | |
| 3 M | 616 | 85.9 (−) | 100.0 | — | — | 0.9908 |
| 658 | 58.7 (+) | 100.0 | — | — | 0.9976 | |
| 4 M | 616 | 24.8 (−) | 100.0 | — | — | 0.9922 |
| 658 | 20.8 (+) | 100.0 | — | — | 0.9888 | |
| 5 M | 616 | 33.1 (−) | 45.1 | 0.21 (−) | 54.9 | 0.9883 |
PCB-ApcEΔΔ in KPB (20 mM, pH 7.2) containing NaCl (0.15 M) was mixed with an appropriate amount of 8 M urea in the same buffer in a stopped-flow apparatus, and the absorptions were monitored at 616 or 658 nm. Absorption changes were fitted with single or, if necessary, biexponential models. Absorption increases are indicated by a plus sign, and decays are indicated by a minus sign.