TABLE 1

Binding affinity of CO and other gaseous signaling molecules to various targets

TargetKd for COKd for NOKd for H2SKd for O2Ki for COComments
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)
Mb29 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)
Ngb0.2 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)
Cyb0.29 μM (dimer); 68 nM (monomer) (Tsujino et al., 2014; Beckerson et al., 2015)
sGC260 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)NRNRNRChange 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).
CBS1.5 ± 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)NRNRNR0.7 μM (Vicente et al., 2016)
Reduced form COX0.3 μM (Gibson and Greenwood, 1963)a0.2 nM (Cooper et al., 2008)No bindingLow O2 (5 μM):second-order rate constant: (Gibson and Greenwood, 1963) 3 × 107 to 6 × 107 M−1 s−10.32 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)
NPAS21–2 μM, 21 μM (Dioum et al., 2002)Reacts irreversibly3 μM impairs DNA binding (Dioum et al., 2002)
CLOCK0.1 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)aBetween 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.
P4501.4–10 μM (Debey et al., 1973)
P450 isoforms0.35 (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 c20 nM (Kapetanaki et al., 2009)
Eosinophil peroxidase18 μM (Abu-Soud and Hazen, 2001)a18 μM (Abu-Soud and Hazen, 2001)
Lactoperoxidase2.2 μM (Abu-Soud and Hazen, 2001)a;20.71 μM (Abu-Soud and Hazen, 2001)a46 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-Lactoglobulin0.5 μM (heme-CO complex) (Marden et al., 1994)
Calmodulin0.5 μM (heme-CO complex) (Leclerc-L'Hostis et al., 1996)
Myeloperoxidase1.6 mM (Murphy et al., 2010)a (pH 6.3)
Hemopexin0.22 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.