CYGB dioxygenates NO

Stable Identifier
Reaction [transition]
Homo sapiens
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Vertebrates possess multiple respiratory globins that differ in structure, function, and tissue distribution. Three different globins have been described so far: haemoglobin facilitates oxygen transport in blood, myoglobin mediates oxygen transport and storage in the muscle and neuroglobin has a yet unidentified function in nerve cells. A fourth globin has been identified in mouse, human and zebrafish. It is ubiquitously expressed in human tissue and therefore called cytoglobin (CYGB) (Trent & Hargrove 2002). Unlike the specific expression patterns of Hb and Mb, CYGB is found in vascular smooth muscle, fibroblasts and cardiomyocytes. CYGB functions as a homodimer (Hamdane et al. 2003) and is localised to the cytosol. As well as oxygen binding capability, CYGB possesses nitric oxide dioxygenase activity (Halligan et al. 2009), a common feature amongst the globin family (Smagghe et al. 2008). CYGB consumes NO through the dioxygenase pathway, which regulates cell respiration and proliferation (Smagghe et al. 2008). O2 binds to the ferric form of CYGB (CYGB-Fe2+:O2). During NO dioxygenation, CYGB is reduced to the ferrous form (CYGB-Fe3+) (Gardner 2005).
Literature References
PubMed ID Title Journal Year
19147491 Cytoglobin is expressed in the vasculature and regulates cell respiration and proliferation via nitric oxide dioxygenation

Jourd'heuil, FL, Halligan, KE, Jourd'heuil, D

J. Biol. Chem. 2009
14530264 The redox state of the cell regulates the ligand binding affinity of human neuroglobin and cytoglobin

Hankeln, T, Burmester, T, Pesce, A, Hamdane, D, Bolognesi, M, Kiger, L, Marden, MC, Uzan, J, Dewilde, S, Moens, L, Green, BN

J. Biol. Chem. 2003
11893755 A ubiquitously expressed human hexacoordinate hemoglobin

Hargrove, MS, Trent, JT

J. Biol. Chem. 2002
18446211 NO dioxygenase activity in hemoglobins is ubiquitous in vitro, but limited by reduction in vivo

Hargrove, MS, Trent JT, 3rd, Smagghe, BJ

PLoS One 2008
15598505 Nitric oxide dioxygenase function and mechanism of flavohemoglobin, hemoglobin, myoglobin and their associated reductases

Gardner, PR

J. Inorg. Biochem. 2005
Catalyst Activity

nitric oxide dioxygenase activity of CYGB dimer:O2 [cytosol]

Orthologous Events
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