Table 2. Values of the second-order rate constant for the nitrite-reductase activity of ferrous heme-proteins.
| Heme-protein | k app (M–1 s–1) |
| Synechocystis hemoglobin a | 6.8×101 |
| Arabidopsis thaliana hemoglobin class 1 b | 2.0×101 |
| Arabidopsis thaliana hemoglobin class 2 b | 4.9 |
| Rice nonsymbiotic hemoglobin class 1 a | 3.3×101 |
| Methanosarcina acetivorans protoglobin* - fast c | 9.6 |
| – slow c | 1.2 |
| Carp myoglobin-1 d | 5.3 |
| Carp myoglobin-2 d | 1.8 |
| Horse heart myoglobin e | 2.9 |
| Sperm whale myoglobin f | 6.0 |
| Sperm whale myoglobin HisE7Ala mutant g | 1.8 |
| Sperm whale myoglobin HisE7Leu mutant g | <0.2 |
| Mouse neuroglobin h | 5.1 |
| Human cytoglobin i | 1.4×10–1 |
| Human neuroglobin CysCD4-CysD5 j | 1.2×10–1 |
| Human neuroglobin CysCD4/CysD5 k | 1.2×10–1 |
| Human neuroglobin CysCD4Ala mutant l | 5.8×10–2 |
| Human neuroglobin CysD5Ala mutant l | 6.0×10–2 |
| Human neuroglobin HisE7Leu mutant l | 2.6×102 |
| Human neuroglobin HisE7Gln mutant l | 2.7×102 |
| Human hemoglobin - T state f | 1.2×10–1 |
| – R state f | 6.0 |
| Human serum heme-albumin m | 1.3 |
| Warfarin-bound human serum heme-albumin m | 9.3×10–2 |
| Horse heart cytochrome c n | 7.0×10–2 |
a
pH 7.0; unknown temperature [42].
b
pH 7.4 and 25°C. From [45].
c
CysE20Ser mutant. pH 7.4 and 20°C. Present study.
d
pH 7.6 and 25°C. From [49].
e
pH 7.4 and 25°C. From [43].
f
pH 7.4 and 25°C. From [37].
g
pH 7.4 and 25°C. From [43].
h
pH 7.4 and 25°C. From [40].
i
pH 7.0 and 25°C. From [44].
j
pH 7.4 and 25°C. From [43]. In “Human neuroglobin CysCD4-CysD5”, the CysCD4 and CysD5 residues form an intramolecular disulphide bond.
k
pH 7.4 and 25°C. From [43]. In “Human neuroglobin CysCD4/CysD5”, the CysCD4 and CysD5 residues do not form the intramolecular disulphide bond.
l
pH 7.4 and 25°C. From [43].
m
pH 7.4 and 20°C. From [46].
n
pH 7.4 and 25°C. From [44].