Heme Oxygenase 1 (HO-1, HSP32, Heat Shock Protein 2)

Heme oxygenase is the rate-limiting microsomal enzyme in the heme degradative pathway. Heme oxygenase catalyzes the NADPH, O2 and cytochrome P450 reductase dependent oxidation of heme to form equimolar biliverdin, carbon monoxide, a putative neurotransmitter, and iron. Biliverdin is subsequently converted to bilirubin by biliverdin reductase. These products of the HO reaction have important physiological effects: carbon monoxide is a potent vasodilator; biliverdin and its product bilirubin are potent antioxidants; "free' iron increases oxidative stress and regulates the expression of many mRNAs...