This review describes the use of cryoreduction/annealing EPR/ENDOR techniques for determining the active oxidizing species in reactions catalyzed by heme monooxygenases. The three candidate heme states are: ferric peroxo, ferric hydroperoxo and compound I intermediates. The enzymes discussed include cytochromes P450, nitric oxide synthase and heme oxygenase.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3021649PMC
http://dx.doi.org/10.1016/j.abb.2010.09.013DOI Listing

Publication Analysis

Top Keywords

cryoreduction/annealing epr/endor
8
active intermediates
4
heme
4
intermediates heme
4
heme monooxygenase
4
monooxygenase reactions
4
reactions revealed
4
revealed cryoreduction/annealing
4
epr/endor studies
4
studies review
4

Similar Publications

In this report, we investigate the physical and chemical properties of monocopper Cu(I) superoxo and Cu(II) peroxo and hydroperoxo complexes. These are prepared by cryoreduction/annealing of the parent [LCu(O)] Cu(I) dioxygen adducts with the tripodal, N-coordinating, tetradentate ligands L = tmpa, tmpa, TMGtren and are best described as [LCu(O)] Cu(II) complexes that possess end-on (η-O) superoxo coordination. Cryogenic γ-irradiation (77 K) of the EPR-silent parent complexes generates mobile electrons from the solvent that reduce the [LCu(O)] within the frozen matrix, trapping the reduced form fixed in the structure of the parent complex.

View Article and Find Full Text PDF

Cytochrome P450scc (CYP 11A1) catalyzes the conversion of cholesterol (Ch) to pregnenolone, the precursor to steroid hormones. This process proceeds via three sequential monooxygenation reactions: two hydroxylations of Ch first form 22(R)-hydroxycholesterol (HC) and then 20α,22(R)-dihydroxycholesterol (DHC); a lyase reaction then cleaves the C20-C22 bond to form pregnenolone. Recent cryoreduction/annealing studies that employed electron paramagnetic resonance (EPR)/electron nuclear double resonance (ENDOR) spectroscopy [Davydov, R.

View Article and Find Full Text PDF

This review describes the use of cryoreduction/annealing EPR/ENDOR techniques for determining the active oxidizing species in reactions catalyzed by heme monooxygenases. The three candidate heme states are: ferric peroxo, ferric hydroperoxo and compound I intermediates. The enzymes discussed include cytochromes P450, nitric oxide synthase and heme oxygenase.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!