TABLE 3.
Effect of nitrosylation or sulfhydration on the FAD-apoprotein hDAAO complex. The cofactor dissociation constants (Kd) determined by measuring the protein fluorescence quenching during the titration of the apoprotein with FAD in the absence or presence of different concentrations of the NO donor GSNO or of the H2S donor NaHS, under different buffer conditions.
| GSNO (µM) | NaHS (µM) | |||||
|---|---|---|---|---|---|---|
| 0 | 50 | 500 | 0 | 5 | 40 | |
| First phase | ||||||
| Kd (µM) | 0.35 ± 0.02 | 0.34 ± 0.04 | 0.31 ± 0.02 | 0.43 ± 0.02 | 0.31 ± 0.03 | 0.33 ± 0.02 |
| Amplitude (%) | 45 | 46 | 44 | 42 | 50 | 48 |
| Second phase | ||||||
| Kd (µM) | 24.2 ± 2.1 | 23.0 ± 2.0 | 26.7 ± 2.3 | ≥30 | 27.5 ± 3.2 | 27.8 ± 3.2 |
| Amplitude (%) | 55 | 54 | 56 | 58 | 50 | 52 |