title: Mechanism of action of heme oxygenase. A study of heme degradation to bile pigment by 18O labeling.
abstract: The formation of bile pigment from heme by a reconstituted heme oxygenase system containing purified bovine spleen heme oxygenase, NADPH-cytochrome P-450 reductase, and biliverdin reductase was studied under an atmosphere containing 18,18O2. The product, bilirubin, was isolated and subjected to mass spectrometry, which revealed incorporation of 18O consistent with a two-molecule mechanism, whereby the product bile pigment contains oxygen atoms derived from two different oxygen molecules.
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000302:isolation & purification; D002374:Catalase / Q000378:metabolism; D002417:Cattle; D006418:Heme / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D007553:Isotope Labeling / Q000379:methods; D013058:Mass Spectrometry; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010103:Oxygen Isotopes; D013154:Spleen / Q000201:enzymology*
chemical_list: D010103:Oxygen Isotopes; D006418:Heme; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D002374:Catalase; D006419:Heme Oxygenase (Decyclizing); D044925:Oxidoreductases Acting on CH-CH Group Donors; C019789:biliverdin reductase; D009251:NADPH-Ferrihemoprotein Reductase; D001663:Bilirubin