TABLE 1.
Binding affinity of CO and other gaseous signaling molecules to various targets
| Target | Kd for CO | Kd for NO | Kd for H2S | Kd for O2 | Ki for CO | Comments |
|---|---|---|---|---|---|---|
| Hb alpha (T) | 1.8 μM (Vandegriff et al., 1991; Unzai et al., 1998) | 0.15 nM (Cooper, 1999) | 422 μM (Sharma et al., 1978) | |||
| Hb beta (T) | 4.5 μM (Vandegriff et al., 1991; Unzai et al., 1998) | |||||
| Hb alpha (R) | 1.7 nM (Vandegriff et al., 1991; Unzai et al., 1998) | 0.9 pM (Cooper, 1999) | 17 μM (to MetHb) (Bostelaar et al., 2016) | 0.3–1 μM (Brunori et al., 1972) | ||
| Hb beta (R) | 0.7 nM (Vandegriff et al., 1991; Unzai et al., 1998) | |||||
| Mb | 29 nM (Gibson et al., 1986; Moffet et al., 2001) | 70 pM (Cooper, 1999) | 18.5 μM (to MetMb) (Kraus et al., 1990) | 0.8 μM (Gibson et al., 1986; Moffet et al., 2001) | ||
| Ngb | 0.2 nM (Dewilde et al., 2001; Azarov et al., 2016) | 1 nM (Trashin et al., 2016) | 370 μM (Ruetz et al., 2017) | 3.2 nM (Dewilde et al., 2001) | ||
| Cyb | 0.29 μM (dimer); 68 nM (monomer) (Tsujino et al., 2014; Beckerson et al., 2015) | |||||
| sGC | 260 μM (human) (Martin et al., 2006); 98 ± 15 μM (bovine) (Stone and Marletta, 1998) | 4.2 pM (Martin et al., 2006) | 1 pM (Cooper, 1999) | H2S stabilizes the NO responsive form. | ||
| sGC (in presence of YC-1) | 94 ± 14 μM (bovine) similar activation effects to NO (100 μM) (Stone and Marletta, 1998).Kd decreases about 20- to 50-fold in mouse-derived sGC. | YC-1 potentiates the effect of NO on sGC by 27%. (Friebe and Koesling, 1998) | NR | NR | NR | Change in Kd of CO in presence of YC-1 varies among different species.YC-1 binds sGC: Kd of 9 − 21 μM and 0.6 − 1.1 μM (CO); BAY 41-2272 binds sGC: Kd = 30 − 90 nM in the presence of CO (Purohit et al., 2014). |
| CBS | 1.5 ± 0.1 μM (Puranik et al., 2006); 68 ± 14 μM (Puranik et al., 2006) (dimeric binding);45 μM (Vicente et al., 2016) | 281 ± 50 μM (Taoka and Banerjee, 2001);<0.23 μM (Vicente et al., 2014) | Oxidation to Fe(III) | 5.6 ± 1.9 μM (Taoka et al., 1999);9.5 μM (Vicente et al., 2016) | ||
| CBS (AdoMet) | 4.5 μM (Vicente et al., 2016) | NR | NR | NR | 0.7 μM (Vicente et al., 2016) | |
| Reduced form COX | 0.3 μM (Gibson and Greenwood, 1963)a | 0.2 nM (Cooper et al., 2008) | No binding | Low O2 (5 μM):second-order rate constant: (Gibson and Greenwood, 1963) 3 × 107 to 6 × 107 M−1 s−1 | 0.32 μM (Petersen, 1977);1.44 μM (normoxic, HEK cells) (D’Amico et al., 2006);0.35 μM (hypoxic, HEK cells) (D’Amico et al., 2006) | |
| NPAS2 | 1–2 μM, 21 μM (Dioum et al., 2002) | Reacts irreversibly | 3 μM impairs DNA binding (Dioum et al., 2002) | |||
| CLOCK | 0.1 mM (Minegishi et al., 2018) | |||||
| KATP channel (heme-HBD complex) |
0.6 ± 0.3 μM (Kapetanaki et al., 2018)a | |||||
| Kv channel (Kv11.3, heme-HBD complex) | 1.03 ± 0.37 μM (Burton et al., 2020)a | Between CO-heme complex and HBD: 10.55 ± 1.34 μM (Burton et al., 2020) | ||||
| BKCa channel (heme-HBD complex) | 50 nM (Yi et al., 2010)a (reduced state) |
Redox state of the Cys residues on HBD affects ligand binding affinity. | ||||
| P450 | 1.4–10 μM (Debey et al., 1973) | |||||
| P450 isoforms | 0.35 (DB1), 1.1 (TB), 3.9 μM (NF) (Leemann et al., 1994) | pH-insensitive (PB); (Oertle et al., 1985) effect of other factors on affinity: (Balny and Debey, 1976; Davydov et al., 1980, 1986; Gray, 1982; Tuckey and Kamin, 1983; Mitani et al., 1985; Khanina et al., 1987) 770 nM (rabbit) (Rösen and Stier, 1973) | ||||
| Cardiolipin-cytochrome c | 20 nM (Kapetanaki et al., 2009) | |||||
| Eosinophil peroxidase | 18 μM (Abu-Soud and Hazen, 2001)a | 18 μM (Abu-Soud and Hazen, 2001) | ||||
| Lactoperoxidase | 2.2 μM (Abu-Soud and Hazen, 2001)a;20.71 μM (Abu-Soud and Hazen, 2001)a | 46 μM (Abu-Soud and Hazen, 2001) | Two binding forms (Abu-Soud and Hazen, 2001) | |||
| Chloroperoxidase (ferrous form, bacterial) | Neutral form: (Campbell et al., 1982);30.5 μMa; acidic form: (Campbell et al., 1982) 0.2 Ma | |||||
| β-Lactoglobulin | 0.5 μM (heme-CO complex) (Marden et al., 1994) | |||||
| Calmodulin | 0.5 μM (heme-CO complex) (Leclerc-L'Hostis et al., 1996) | |||||
| Myeloperoxidase | 1.6 mM (Murphy et al., 2010)a (pH 6.3) | |||||
| Hemopexin | 0.22 μM (Shaklai et al., 1981)a (pH 8);2.5 μM (Shaklai et al., 1981)a (pH 6) | |||||
| NOS (White and Marletta, 1992) | 10−3 μM and 100 μM in the absence and presence of substrate and cofactor, respectively | (Sato et al., 1998; Bengea et al., 2003, 2004) |
aSome data are calculated from reported kon and koff values. NR, not reported.