Unusual Cytochrome P450 Enzymes and Reactions

Guengerich, F. Peter; Munro, Andrew W.

doi:10.1074/jbc.r113.462275

Cited by 290 publications

(221 citation statements)

References 97 publications

(44 reference statements)

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“…We highlighted the role of the ferric heme proteins in the degradation of both adducts involving oxidation of the aminoxyl moiety of BMPO-OH to an unstable oxoammonium cation that further evolved to yield a -hydroxynitrone and its cyclic hydroxamic acid tautomers [52][53][54] (Scheme 2, c), while the alkylhydroperoxide moiety of BMPO-OOH would be cleaved either homolytically into ring-opened diamagnetic products or heterolytically into BMPO-OH [29] (Scheme 2, a). Besides, biological reductants such as ascorbic acid and glutathione, and flavin dependent reductases, including P450 reductase, were involved in the rapid loss of the ESR signals of both BMPO-OOH and BMPO-OH in the presence of RLC.…”

Section: Discussionmentioning

confidence: 99%

“…They display higher reaction rates with superoxide (three times that of DEPMPO for Mito-DEPMPO and CD-DEPMPO [10] ) and their adducts show a highly increased stability in buffer in comparison with those of DEPMPO or BMPO. However the stability of the spin adducts of these new probes have not yet been evaluated in the presence of biological oxidoreductants and liver subcellular fractions that contain most of the enzymes involved in the metabolism of xenobiotics, such as cytochrome P450 [29] .…”

Section: Introductionmentioning

confidence: 99%

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Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps

Bézière

Hardy

Poulhès

et al. 2014

Free Radical Biology and Medicine

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Reactive oxygen species (ROS) are by-products of aerobic metabolism involved in the onset and evolution of various pathological conditions. Among them, superoxide radical is of special interest as the origin of several damaging species such as H 2 O 2 , hydroxyl radical, or peroxynitrite (ONOO -). Spin trapping coupled with ESR is a method of choice to characterize these species in chemical and biological systems and the metabolic stability of the spin adducts derived from reaction of superoxide and hydroxyl radicals with nitrones is the main limit to the in vivo application of the method. Recently, new cyclic nitrones bearing a triphenylphosphonium or cyclodextrin moiety have been synthesized and their spin adducts demonstrated increased stability in buffer. In the present manuscript, we studied the stability of the superoxide adducts of four new cyclic nitrones in the presence of liver subcellular fractions and biologically relevant reductants using an original set up combining a stoppedflow device and an ESR spectrometer. The kinetics of disappearance of the spin adducts were analyzed using an appropriate simulation program. Our results highlight the interest of new spin trapping agents CD-DEPMPO and CD-DIPPMPO for specific detection of superoxide with high stability of the superoxide adducts in the presence of liver microsomes.3

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps

Bézière

Hardy

Poulhès

et al. 2014

Free Radical Biology and Medicine

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“…The widely distributed heme-thiolate monooxygenases, such as cytochrome P450 (CYP), serve similar roles in catalyzing C−H hydroxylation reaction. CYP enzymes also participate in the primary pathways for oxidative steroid and prostaglandin biosynthesis as well as phase I drug metabolism (8)(9)(10)(11)(12). For example, 20 isoforms of CYP with significant physiological functions exist in Mycobacterium tuberculosis, making them potential drug targets (13).…”

mentioning

confidence: 99%

Heme-thiolate ferryl of aromatic peroxygenase is basic and reactive

Wang

Ullrich

Hofrichter

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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A kinetic and spectroscopic characterization of the ferryl intermediate (APO-II) from APO, the heme-thiolate peroxygenase from Agrocybe aegerita, is described. APO-II was generated by reaction of the ferric enzyme with metachloroperoxybenzoic acid in the presence of nitroxyl radicals and detected with the use of rapidmixing stopped-flow UV-visible (UV-vis) spectroscopy. The nitroxyl radicals served as selective reductants of APO-I, reacting only slowly with APO-II. APO-II displayed a split Soret UV-vis spectrum (370 nm and 428 nm) characteristic of thiolate ligation. Rapid-mixing, pHjump spectrophotometry revealed a basic pK a of 10.0 for the Fe IV −O−H of APO-II, indicating that APO-II is protonated under typical turnover conditions. Kinetic characterization showed that APO-II is unusually reactive toward a panel of benzylic C−H and phenolic substrates, with second-order rate constants for C−H and O−H bond scission in the range of 10-10 7 M −1 ·s −1 . Our results demonstrate the important role of the axial cysteine ligand in increasing the proton affinity of the ferryl oxygen of APO intermediates, thus providing additional driving force for C−H and O−H bond scission.

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“…These heme-thiolate mono-oxygenases often catalyze the insertion of oxygen into carbon-hydrogen bonds to produce hydroxyl groups, although they can mediate more complex reactions as well (Guengerich and Munro, 2013). In any case, the addition of oxygen both increases polarity/solubility and imparts hydrogenbonding capacity, enabling specific binding interactions, as well as providing functional groups for further modification.…”

Section: Terpenoid Metabolismmentioning

confidence: 99%

The application of synthetic biology to elucidation of plant mono-, sesqui- and diterpenoid metabolism

Kitaoka¹,

Lu²,

Yang³

et al. 2014

Molecular Plant

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Plants synthesize a huge variety of terpenoid natural products, including photosynthetic pigments, signaling molecules and defensive substances. These are often produced as complex mixtures, presumably shaped by selective pressure over evolutionary timescales, some of which have been found to have pharmaceutical and other industrial uses. Elucidation of the relevant biosynthetic pathways can provide increased access (e.g., via molecular breeding or metabolic engineering), and enable reverse genetic approaches towards understanding the physiological role of these natural products in plants as well. While such information can be obtained via a variety of approaches, this review describes the emerging use of synthetic biology to recombinantly reconstitute plant terpenoid biosynthetic pathways in heterologous host organisms as a functional discovery tool, with a particular focus on incorporation of the historically problematic cytochrome P450 mono-oxygenases. Also falling under the synthetic biology rubric and discussed here is the nascent application of genome-editing tools to probe physiological function.

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Unusual Cytochrome P450 Enzymes and Reactions

Cited by 290 publications

References 97 publications

Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps

Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps

Heme-thiolate ferryl of aromatic peroxygenase is basic and reactive

The application of synthetic biology to elucidation of plant mono-, sesqui- and diterpenoid metabolism

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