Table 2.
Kinetic and thermodynamic parameters for cyanide binding to selected heme proteins with varying distal pockets
| Protein | conditions | kon/M−1 s−1 | koff/s−1 | KD/M | reference |
|---|---|---|---|---|---|
| KpCld | 20 °C, pH 7.0 | (1.15±0.01)×106 | (5.8±3.2)×10−3a | (4.7±2.8)×10−9b | This work |
| DaCld | 20 °C, pH 7.0 | (1.30±0.02)×106 | (8±1)×10−1 | (6.1±0.4) ×10−7c | This work |
| CCld | 25 °C, pH 7.0 | 1.6×105 | 1.4 | 8.6×10−6 | 11 |
| NwCld | 25 °C, pH 7.0 | 1.0×106 | 2.4 | 2.4×10−6 | 67 |
| NdCld | 25 °C, pH 7.0 | 2.57×106 | 9.3 | 3.6×10−6 | 23 |
| CcP | 25 °C, pH 7.0 | 1.1×105 | 9.0×10−1 | 8×10−6 | 68 |
| CcP(H52L) | 25 °C, pH 7.0 | 7.0×103 | 1.5×10−1 | 6.3×10−6 | 34 |
| HRP | 25 °C, pH 7.05 | 9.8×104 | 2.8×10−1 | 2.9×10−6 | 35 |
| Cj trHbPd | 20 °C, pH 7.0 | ≥ 2×104 | ≥ 1×10−4 | 5.8×10−9 | 69, 70 |
| Mt trHbNd | 20 °C, pH 7.0 | 3.80×102 | 6.8×10−4 | 1.8×10−6 | 69, 70 |
| Mt trHbOd | 20 °C, pH 7.0 | 3.20×102 | 3.5×10−4 | 1.1×10−6 | 69, 70 |
| Human Mb | 20 °C, pH 7.0 | 2.30×102 | 3.8×10−4 | 1.67×10−6 | 71, 72 |
| SW Mb | 20 °C, pH 7.0 | 3.20×102 | 4.0×10−4 | 1.25×10−6 | 71, 72 |
| Human Mb(H64A) | 20 °C, pH 7.0 | 1.1×102 | 4.6×10−4 | 4.17×10−6 | 72 |
| Human Mb(H64Q) | 20 °C, pH 7.0 | 1.8×102 | 1.0×10−5 | 5.6×10−8 | 71, 72 |
| BjFixLHd | 25 °C, pH 7.0 | 1.8×101 | 1.2×10−4 | 5.2×10−6 | 73 |
| SmFixLHd | 25 °C, pH 7.0 | 1.4×101 | 1.7×10−4 | 1.04×10−5 | 73 |
| SmFixLNd | 22 °C, pH 7.0 | 3.2×101 | 14.7×10−4 | 1.48×10−5 | 49 |
| Microperoxidase-11 | 20 °C, pH 7.0 | 8.9×103 | 1.5×10−3 | 1.7×10−7 | 74 |
| DaCld(R183Q) | 20 °C, pH 7.0 | (3.0±0.02)×103 | (1.7±0.2)×10−1 | (6.0±0.6)×10−5 | This work |
| NdCld(R173Q) | 25 °C, pH 7.0 | 2.3×103 | 5×10−1 | 2.164×10−4 | 25 |
| NdCld(R173K) | 25 °C, pH 7.0 | 1.62×103 | 3.0×10−1 | 1.85×10−4 | 23 |
| NdCld(R173A) | 25 °C, pH 7.0 | 3.43×103 | 5.01×10−1 | 1.46×10−4 | 23 |
| NdCld(R173E) | 25 °C, pH 7.0 | 7.3×101 | 3.0×10−1 | 3.874×10−3 | 25 |
| CcP(H52Q) | 25 °C, pH 6.0 | 8.4×101 | 4.9×10−2 | 6.1×10−3 | 33 |
| Gd II Hb+d | 20 °C, pH 7.0 | 4.91 ×10−1 | 9.82 ×10−8 | 2 ×10−7 | 75 |
| Gd III Hb+d | 20 °C, pH 7.0 | 3.02 ×10−1 | 2.9 ×10−6 | 1×10−5 | 76 |
| Gd IV Hb+d | 20 °C, pH 7.0 | 1.82 | 2.2 ×10−5 | 1.2 ×10−5 | 76 |
a
Calculated from spectrophotometric KD and kinetically determined kon.
b
Measured via spectrophotometric titration.
c
Kinetic and spectrophotometric titration yield the same value for DaCld KD.
d
Cj, Campylobacter jejuni;Mt, Mycobacterium tuberculosis; Bj, Bradyrhizobium japonicum; Sm, Sinorhizobium meliloti; Gd, Glycera dibranchiate.