Heme oxygenase provides alpha-selectivity to physiological heme degradation
Docherty, J.C.; Masters, B.S.; Firneisz, G.D.; Schacter, B.A.
Biochemical and Biophysical Research Communications 105(3): 1005-1013
1982
ISSN/ISBN: 0006-291X PMID: 6807308 Document Number: 183867
The isomeric composition of biliverdin formed by the degradation of heme by purified NADPH-cytochrome c reductase was determined by high performance liquid chromatography. Methemalbumin heme yields a mixture of the 4 biliverdin IX isomers while myoglobin yields only the IX-.alpha. isomer of biliverdin. In both cases biliverdin is a minor product of the reaction. Addition of purified heme oxygenase to the methemalbumin NADPH-cytochrome c reductase system confers .alpha.-selectivity on the reaction and allows stoichiometric conversion of heme to biliverdin. Thus the role of heme oxygenase in enzymatic heme degradation appears to be to provide a suitable environment for quantitative conversion of heme to biliverdin in addition to conferring .alpha.-selectivity on the reaction.