Enzymic conversion of α-oxyprotohaem IX into biliverdin IXα by haem oxygenase
- 15 September 1990
- journal article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 270 (3), 659-664
- https://doi.org/10.1042/bj2700659
Abstract
Conversion of four isomers of meso-oxyprotohaem IX into the corresponding biliverdin IX was attempted with a reconstituted haem oxygenase system in the presence of NADPH-cytochrome c reductase and NADPH. Only the alpha-isomer of meso-oxyprotohaem IX was converted effectively into biliverdin IX alpha, which was further reduced to bilirubin IX alpha by biliverdin reductase. Only trace amounts of biliverdins IX beta, IX gamma and IX delta were respectively formed from the incubation mixture of the corresponding oxyprotohaemin IX isomers with the complete haem oxygenase system under the same conditions. In a kinetic study, the Km for alpha-meso-oxyprotohaem IX was 3.6 microM, which was 2-fold higher than that for protohaem IX. The maximum velocity (Vmax.) of the conversion of alpha-meso-oxyprotohaem IX into biliverdin IX alpha was twice as fast as that of protohaem IX. These results demonstrate that alpha-meso-oxyprotohaem IX is an intermediate of haem degradation and it was converted stereospecifically into biliverdin IX alpha via verdohaem IX alpha.Keywords
This publication has 19 references indexed in Scilit:
- On the mechanism of the chemical and enzymic oxygenations of alpha-oxyprotohemin IX to Fe.biliverdin IX alpha.Proceedings of the National Academy of Sciences, 1986
- Purification and properties of bovine spleen heme oxygenase. Amino acid composition and sites of action of inhibitors of heme oxidation.Journal of Biological Chemistry, 1982
- Verdohemochrome IX alpha: preparation and oxidoreductive cleavage to biliverdin IX alpha.Proceedings of the National Academy of Sciences, 1982
- Specificity of heme oxygenase: a study with synthetic heminsBiochemistry, 1981
- High-performance liquid chromatographic separation and quantification of the four biliverdin dimethyl ester isomers of the IX seriesAnalytical Biochemistry, 1980
- The mechanism of haem catabolism. Bilirubin formation in living rats by [18O]oxygen labellingBiochemical Journal, 1978
- Esterification of hemins with trimethyloxonium tetrafluoroborateAnalytical Biochemistry, 1976
- The meso-reactivity of porphyrins and related compounds. Part VI. Oxidative cleavage of the haem system. The four isomeric biliverdins of the IX seriesJournal of the Chemical Society, Perkin Transactions 1, 1973
- Separation and identification of biliverdin isomers and isomer analysis of phycobilins and bilirubinJournal of Chromatography A, 1970
- Reduced nicotinamide adenine dinucleotide phosphate dependent biliverdin reductase. Partial purification and characterizationBiochemistry, 1970