Physiological roles | Heme degradation | Heme degradation | Heme binding |
(Selection of functions) | Anti-oxidant defense | Heme binding | |
| Modulation of vascular tone and liver perfusion | Maintenance of vascular tone | |
| Neural signaling | Neural signaling | |
| Anti-inflammatory actions | | |
| Down-modulation of adhesion molecule expression | | |
| Regulation of hemo-proteins activity | | |
Constitutive tissue expression | Spleen Liver | Most tissues, e.g.: brain, retina, liver, spleen, testis, lungs, kidney, vasculature | Most tissues |
Inducers of expression | Very diverse, e.g.: oxidative stress, cytokines, heavy metals, hypoxia, nitric oxide, heat shock, endotoxins, heme, UV | Adrenal glucocorticoids, opiates | Not known |
Enzyme activity | Km = 0.24 μM | Km = 0.67 μM | Negligible |
| Vmax = 3.4 μmol/mg/h | Vmax = 0.24 μmol/mg/h |
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