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. 2011 Apr 27;50(21):4491–4503. doi: 10.1021/bi200130r

Table 2. On and Off Rates and Binding Constants for Several Protein-NO (or CO) Complexes.

  kon(M–1 s–1) koff (s–1) KCat-NO = kon/koff (M–1)
Mb(Fe2+)COa 5.1 × 105 1.9 × 10–2 2.7 × 107
Mb(Fe2+)NOa 1.7 × 107 1.2 × 10–4 1.4 × 1011
Mb(Fe3+)NOb 4.8 × 104 42 1.14 × 103
Lb(Fe2+)NOa 1.2 × 108 2.0 × 10–5 5.9 × 1012
NP1(Fe3+)NOc 1.5 × 106 (pH 5) 0.18 (pH 5) 8.3 × 106 (pH 5)
  1.5 × 106 (pH 8) 1.25 (pH 8) 1.2 × 106 (pH 8)
NP4(Fe3+)NOc 2.1 × 106 (pH 5) 0.11 (pH 5) 2.0 × 107 (pH 5)
  2.3 × 106 (pH 8) 1.24 (pH 8) 1.9 × 106 (pH 8)
Cat(Fe3+)NOd 1.3 × 107 1.5 8.7 × 106
a

From ref (60). Lb is leghemoglobin.

b

From ref (67).

c

From ref (64). The nitrophorins adopt closed and open conformations at pH 5 and 8, respectively.

d

From this work.