Variation of the oxidation state of verdoheme in the heme oxygenase reaction.

Heme oxygenase (HO) converts hemin to biliverdin, CO, and iron applying molecular oxygen and electrons. During successive HO reactions, two intermediates, alpha-hydroxyhemin and verdoheme, have been generated. Here, oxidation state of the verdoheme-HO complexes is controversial.

Spectroscopic characterization of a higher plant heme oxygenase isoform-1 from Glycine max (soybean)--coordination structure of the heme complex and catabolism of heme.

Heme oxygenase converts heme into biliverdin, CO, and free iron. In plants, as well as in cyanobacteria, heme oxygenase plays a particular role in the biosynthesis of photoreceptive pigments, such as phytochromobilins and phycobilins, supplying biliverdin IX(alpha) as a direct synthetic resource. In this study, a higher plant heme oxygenase, GmHO-1, of Glycine max (soybean), was prepared to evaluate the molecular features of its heme complex, the enzymatic activity, and the mechanism of heme conversion.