Table 1. Values of the first-order rate constant (k off) for cyanide dissociation from MaPgb*(III)- and mutant-cyanide complexes as well as horse heart Mb(III)-cyanide, at pH 9.2 and 20.0°C.
| Protein | k off (s−1) | Number of H-bonds | Residues H-bonded to cyanide |
| MaPgb*(III) | (5.8±0.4)×10−5 | 2 | Trp(60)B9, Tyr(61)B10 |
| Trp(60)B9Ala | (5.7±0.4)×10−4 | 1 | Tyr(61)B10 |
| Tyr(61)B10Ala | (4.2±0.3)×10−4 | 1 | Trp(60)B9 |
| Phe(93)E11Leu | (6.3±0.5)×10−5 | 1 | Trp(60)B9 |
| Ile(142)G4Ala | (5.1±0.5)×10−5 | 2 | Trp(60)B9, Tyr(61)B10 |
| Ile(149)G11Phe | (6.1±0.6)×10−5 | 2 | Trp(60)B9, Tyr(61)B10 |
| Horse heart Mb [ref. 21] | (4.9±0.4)×10−4 | 1 | His(64)E7 |