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Artikel: Cytochrome P450: nature's most versatile biological catalyst.

Coon, Minor J

Annual review of pharmacology and toxicology

2005 Band 45, Seite(n) 1–25

Abstract: The author describes studies that led to the resolution and reconstitution of the cytochrome P450 enzyme system in microsomal membranes. The review indicates how purification and characterization of the cytochromes led to rigorous evidence for multiple ... ...

Abstract	The author describes studies that led to the resolution and reconstitution of the cytochrome P450 enzyme system in microsomal membranes. The review indicates how purification and characterization of the cytochromes led to rigorous evidence for multiple isoforms of the oxygenases with distinct chemical and physical properties and different but somewhat overlapping substrate specificities. Present knowledge of the individual steps in the P450 and reductase reaction cycles is summarized, including evidence for the generation of multiple functional oxidants that may contribute to the exceptional diversity of the reactions catalyzed.
Mesh-Begriff(e)	Animals ; Catalysis ; Cytochrome P-450 Enzyme System/chemistry ; Cytochrome P-450 Enzyme System/metabolism ; Cytochrome P-450 Enzyme System/physiology ; Humans ; Isoenzymes/chemistry ; Isoenzymes/metabolism ; Isoenzymes/physiology ; Substrate Specificity/physiology
Chemische Substanzen	Isoenzymes ; Cytochrome P-450 Enzyme System (9035-51-2)
Sprache	Englisch
Erscheinungsdatum	2005
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Review
ZDB-ID	196587-6
ISSN	1545-4304 ; 0362-1642
ISSN (online)	1545-4304
ISSN	0362-1642
DOI	10.1146/annurev.pharmtox.45.120403.100030
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Omega oxygenases: nonheme-iron enzymes and P450 cytochromes.

Coon, Minor J

Biochemical and biophysical research communications

2005 Band 338, Heft 1, Seite(n) 378–385

Abstract: Enzymes that effect with ease one of the most difficult chemical reactions, hydroxylation of an unfunctionalized alkyl group, are of particular interest because highly reactive intermediates must be produced. A typical example, the hydroxylation of fatty ...

Abstract	Enzymes that effect with ease one of the most difficult chemical reactions, hydroxylation of an unfunctionalized alkyl group, are of particular interest because highly reactive intermediates must be produced. A typical example, the hydroxylation of fatty acids in the omega position, is now known to occur widely in nature. The catalysts, which can be called "omega-oxygenases," also insert molecular oxygen into a variety of other substrates at positions removed from activating functional groups, as in steroids, eicosanoids, and numerous drugs and other xenobiotics. Progress in the characterization of bacterial nonheme-iron enzymes, and plant, bacterial, and mammalian P450 cytochromes that catalyze fatty acid omega-oxidation, and evidence for multiple functional oxidants are summarized.
Mesh-Begriff(e)	Animals ; Bacterial Proteins/chemistry ; Bacterial Proteins/metabolism ; Bacterial Proteins/physiology ; Catalysis ; Cytochrome P-450 Enzyme System/chemistry ; Cytochrome P-450 Enzyme System/metabolism ; Cytochrome P-450 Enzyme System/physiology ; Nonheme Iron Proteins/chemistry ; Nonheme Iron Proteins/metabolism ; Nonheme Iron Proteins/physiology ; Oxidation-Reduction ; Plant Proteins/chemistry ; Plant Proteins/metabolism ; Plant Proteins/physiology
Chemische Substanzen	Bacterial Proteins ; Nonheme Iron Proteins ; Plant Proteins ; Cytochrome P-450 Enzyme System (9035-51-2)
Sprache	Englisch
Erscheinungsdatum	2005-12-09
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Review
ZDB-ID	205723-2
ISSN	0006-291X ; 0006-291X
ISSN (online)	0006-291X
ISSN	0006-291X
DOI	10.1016/j.bbrc.2005.08.169
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Multiple oxidants and multiple mechanisms in cytochrome P450 catalysis.

Coon, Minor J

Biochemical and biophysical research communications

2003 Band 312, Heft 1, Seite(n) 163–168

Mesh-Begriff(e)	Catalysis ; Cytochrome P-450 Enzyme System/chemistry ; Cytochrome P-450 Enzyme System/metabolism ; Enzyme Activators/chemistry ; Microsomes/enzymology ; Oxidants/chemistry ; Oxidants/metabolism ; Reactive Oxygen Species/chemistry ; Reactive Oxygen Species/metabolism ; Structure-Activity Relationship
Chemische Substanzen	Enzyme Activators ; Oxidants ; Reactive Oxygen Species ; Cytochrome P-450 Enzyme System (9035-51-2)
Sprache	Englisch
Erscheinungsdatum	2003-12-05
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Review
ZDB-ID	205723-2
ISSN	0006-291X ; 0006-291X
ISSN (online)	0006-291X
ISSN	0006-291X
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Enzyme ingenuity in biological oxidations: a trail leading to cytochrome p450.

Coon, Minor J

The Journal of biological chemistry

2002 Band 277, Heft 32, Seite(n) 28351–28363

Mesh-Begriff(e)	Animals ; Biochemistry/history ; Cytochrome P-450 Enzyme System/chemistry ; Cytochrome P-450 Enzyme System/history ; History, 20th Century ; Humans ; Mentors/history ; Models, Chemical ; Oxygen/history ; Oxygen/metabolism ; Switzerland ; United States
Chemische Substanzen	Cytochrome P-450 Enzyme System (9035-51-2) ; Oxygen (S88TT14065)
Sprache	Englisch
Erscheinungsdatum	2002-06-05
Erscheinungsland	United States
Dokumenttyp	Autobiography ; Biography ; Historical Article ; Journal Article ; Portrait
ZDB-ID	2997-x
ISSN	1083-351X ; 0021-9258
ISSN (online)	1083-351X
ISSN	0021-9258
DOI	10.1074/jbc.R200015200
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Oxidative aldehyde deformylation catalyzed by NADPH-cytochrome P450 reductase and the flavoprotein domain of neuronal nitric oxide synthase.

Vatsis, Kostas P / Coon, Minor J

Biochemical and biophysical research communications

2005 Band 337, Heft 4, Seite(n) 1107–1111

Abstract: We report here the unexpected finding that recombinant or hepatic microsomal NADPH-cytochrome P450 reductase catalyzes the oxidative deformylation of a model xenobiotic aldehyde, 2-phenylpropionaldehyde, to the n-1 alcohol, 1-phenylethanol, in the ... ...

Abstract	We report here the unexpected finding that recombinant or hepatic microsomal NADPH-cytochrome P450 reductase catalyzes the oxidative deformylation of a model xenobiotic aldehyde, 2-phenylpropionaldehyde, to the n-1 alcohol, 1-phenylethanol, in the absence of cytochrome P450. The flavoprotein and NADPH are absolute requirements, and the reaction displays a dependence on time and on NADPH and reductase concentration. Not surprisingly, the hydrophobic tail of the flavoprotein is not required for catalytic competence. The reductase domain of neuronal nitric oxide synthase is about 30% more active than P450 reductase, and neither flavoprotein catalyzes conversion of the aldehyde to the carboxylic acid, by far the predominant metabolite with P450s in a reconstituted system. Reductase-catalyzed deformylation is unaffected by metal ion chelators and oxygen radical scavengers, but is strongly inhibited by catalase, and the catalase-mediated inhibition is prevented by azide. These results, together with observed parallel increases in 1-phenylethanol and H(2)O(2) formation as a function of NADPH concentration, are evidence that free H(2)O(2) is rate-limiting in aldehyde deformylation by the flavoprotein reductases. This contrasts sharply with the P450-catalyzed reaction, which is brought about by iron-bound peroxide that is inaccessible to catalase.
Mesh-Begriff(e)	Animals ; Benzyl Alcohols/metabolism ; Catalase/metabolism ; Catalysis ; Flavoproteins/chemistry ; Flavoproteins/metabolism ; Formaldehyde/chemistry ; Formaldehyde/metabolism ; Hydrogen Peroxide/metabolism ; NADPH-Ferrihemoprotein Reductase/genetics ; NADPH-Ferrihemoprotein Reductase/metabolism ; Nitric Oxide Synthase Type I/chemistry ; Nitric Oxide Synthase Type I/metabolism ; Oxidation-Reduction ; Rabbits ; Rats
Chemische Substanzen	Benzyl Alcohols ; Flavoproteins ; Formaldehyde (1HG84L3525) ; Hydrogen Peroxide (BBX060AN9V) ; methylphenyl carbinol (E6O895DQ52) ; Catalase (EC 1.11.1.6) ; Nitric Oxide Synthase Type I (EC 1.14.13.39) ; NADPH-Ferrihemoprotein Reductase (EC 1.6.2.4)
Sprache	Englisch
Erscheinungsdatum	2005-12-02
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Research Support, N.I.H., Extramural
ZDB-ID	205723-2
ISSN	0006-291X ; 0006-291X
ISSN (online)	0006-291X
ISSN	0006-291X
DOI	10.1016/j.bbrc.2005.09.167
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Irwin C. Gunsalus, versatile and creative scientist.

Coon, Minor J / Sligar, Stephen G

Biochemical and biophysical research communications

2003 Band 312, Heft 1, Seite(n) 1–6, 9–27

Mesh-Begriff(e)	Bacteriology/history ; Biochemistry/history ; Cytochrome P-450 Enzyme System/history ; Cytochrome P-450 Enzyme System/metabolism ; History, 20th Century ; Molecular Biology/history ; Pyridoxal Phosphate/history ; Thioctic Acid/history ; United Nations/history ; United States
Chemische Substanzen	Pyridoxal Phosphate (5V5IOJ8338) ; Thioctic Acid (73Y7P0K73Y) ; Cytochrome P-450 Enzyme System (9035-51-2)
Sprache	Englisch
Erscheinungsdatum	2003-12-05
Erscheinungsland	United States
Dokumenttyp	Bibliography ; Biography ; Historical Article ; Journal Article ; Portraits
ZDB-ID	205723-2
ISSN	0006-291X ; 0006-291X
ISSN (online)	0006-291X
ISSN	0006-291X
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Ipso-substitution by cytochrome P450 with conversion of p-hydroxybenzene derivatives to hydroquinone: evidence for hydroperoxo-iron as the active oxygen species.

Vatsis, Kostas P / Coon, Minor J

Archives of biochemistry and biophysics

2002 Band 397, Heft 1, Seite(n) 119–129

Abstract: Evidence for multiple functional active oxidants in cytochrome P450-catalyzed reactions was previously obtained in this laboratory with mutants in which proton delivery was perturbed by replacement of the highly conserved threonine residue in the active ... ...

Abstract	Evidence for multiple functional active oxidants in cytochrome P450-catalyzed reactions was previously obtained in this laboratory with mutants in which proton delivery was perturbed by replacement of the highly conserved threonine residue in the active site by alanine, thus apparently interfering with the conversion of the peroxo-iron to the hydroperoxo-iron and the latter to the oxenoid-iron species. These enzymes have now been employed to examine the reaction in which cytochrome P450 in liver microsomes is known to effect ipso-substitution, the elimination of p-substituents in phenols to yield hydroquinone. As shown with purified NH(2)-truncated cytochromes in a reconstituted enzyme system, the reaction exhibits an absolute requirement for cytochrome P450 and NADPH-cytochrome P450 reductase. Under optimal conditions truncated cytochrome P450 2E1 is active with 10 of the p-substituted phenols examined. Of particular interest, the corresponding cytochrome with threonine-303 replaced by alanine is from 1.5- to 50-fold higher in activity with the p-chloro, -bromo, -nitro, -cyano, -hydroxymethyl, -formyl, and -acetyl derivatives, and the reaction with the p-benzoyl, -methyl, and -t-butyl compounds is catalyzed by the mutant enzyme only. The results implicate the hydroperoxo-iron species as an electrophilic active oxidant in cytochrome P450-catalyzed aromatic ipso-substitution.
Mesh-Begriff(e)	Anti-Infective Agents, Local/chemistry ; Anti-Infective Agents, Local/metabolism ; Catalysis ; Cloning, Molecular ; Cytochrome P-450 Enzyme System/chemistry ; Escherichia coli/enzymology ; Hydrogen Peroxide/chemistry ; Hydrogen-Ion Concentration ; Iron/chemistry ; Kinetics ; Models, Chemical ; NADP/metabolism ; Oxygen/metabolism ; Phenol/chemistry ; Phenol/metabolism ; Protein Binding ; Reactive Oxygen Species ; Time Factors
Chemische Substanzen	Anti-Infective Agents, Local ; Reactive Oxygen Species ; Phenol (339NCG44TV) ; NADP (53-59-8) ; Cytochrome P-450 Enzyme System (9035-51-2) ; Hydrogen Peroxide (BBX060AN9V) ; Iron (E1UOL152H7) ; Oxygen (S88TT14065)
Sprache	Englisch
Erscheinungsdatum	2002-01-01
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Research Support, U.S. Gov't, P.H.S.
ZDB-ID	523-x
ISSN	1096-0384 ; 0003-9861
ISSN (online)	1096-0384
ISSN	0003-9861
DOI	10.1006/abbi.2001.2665
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Peroxidase-like activity of uncoupled cytochrome P450: studies with bilirubin and toxicological implications of uncoupling.

De Matteis, Francesco / Ballou, David P / Coon, Minor J / Estabrook, Ronald W / Haines, Donovan C

Biochemical pharmacology

2012 Band 84, Heft 3, Seite(n) 374–382

Abstract: The NADPH-dependent consumption of O(2) by cytochrome P450 BM3 was stimulated by either laurate or perfluorolaurate, but the NADPH/O(2) molar consumption ratios were approximately 1 and 2, respectively, indicating that perfluorolaurate does not become ... ...

Abstract	The NADPH-dependent consumption of O(2) by cytochrome P450 BM3 was stimulated by either laurate or perfluorolaurate, but the NADPH/O(2) molar consumption ratios were approximately 1 and 2, respectively, indicating that perfluorolaurate does not become oxygenated by BM3 and oxygen undergoes full reduction to water. The nature of this catalytic cycle uncoupled to hydroxylation was explored using bilirubin as a molecular probe. During uncoupling with perfluorolaurate bilirubin was degraded and stimulated O(2) uptake by an approximately equimolar amount. No stimulation of oxygen uptake was caused by bilirubin in presence of NADPH alone or in presence of laurate together with NADPH; under these conditions little degradation of bilirubin was observed. Mesobilirubin was also degraded during uncoupling with perfluorolaurate, whereas biliverdin (which lacks the central methene bridge present in rubins) was unaffected. It is suggested that the CYP ferryl oxygen species abstracts a hydrogen atom from the central methene bridge of bilirubin to generate a radical, which is further dehydrogenated to biliverdin or else binds O(2) and undergoes fragmentation. We conclude that the uncoupled catalytic cycle of cytochrome P450 has properties resembling those of a peroxidase and that bilirubin is rapidly oxidized as a peroxidase substrate. The potential toxicological significance of cytochrome P450 uncoupling is considered.
Mesh-Begriff(e)	Bacillus megaterium/enzymology ; Bilirubin/metabolism ; Cytochrome P-450 Enzyme System/metabolism ; Cytochrome P-450 Enzyme System/toxicity ; Enzyme Activation/physiology ; NADP/metabolism ; NADPH-Ferrihemoprotein Reductase/metabolism ; Oxidation-Reduction/drug effects ; Peroxidase/metabolism ; Uncoupling Agents/metabolism
Chemische Substanzen	Uncoupling Agents ; NADP (53-59-8) ; Cytochrome P-450 Enzyme System (9035-51-2) ; Peroxidase (EC 1.11.1.7) ; NADPH-Ferrihemoprotein Reductase (EC 1.6.2.4) ; Bilirubin (RFM9X3LJ49)
Sprache	Englisch
Erscheinungsdatum	2012-08-01
Erscheinungsland	England
Dokumenttyp	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	208787-x
ISSN	1873-2968 ; 0006-2952
ISSN (online)	1873-2968
ISSN	0006-2952
DOI	10.1016/j.bcp.2012.04.016
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel: Peroxidase-like activity of uncoupled cytochrome P450: Studies with bilirubin and toxicological implications of uncoupling

De Matteis, Francesco / Ballou, David P / Coon, Minor J / Estabrook, Ronald W / Haines, Donovan C

Biochemical Pharmacology. 2012 Aug. 1, v. 84, no. 3

2012

Abstract: The NADPH-dependent consumption of O₂ by cytochrome P450 BM3 was stimulated by either laurate or perfluorolaurate, but the NADPH/O₂ molar consumption ratios were approximately 1 and 2, respectively, indicating that perfluorolaurate does not become ... ...

Abstract	The NADPH-dependent consumption of O₂ by cytochrome P450 BM3 was stimulated by either laurate or perfluorolaurate, but the NADPH/O₂ molar consumption ratios were approximately 1 and 2, respectively, indicating that perfluorolaurate does not become oxygenated by BM3 and oxygen undergoes full reduction to water. The nature of this catalytic cycle uncoupled to hydroxylation was explored using bilirubin as a molecular probe. During uncoupling with perfluorolaurate bilirubin was degraded and stimulated O₂ uptake by an approximately equimolar amount. No stimulation of oxygen uptake was caused by bilirubin in presence of NADPH alone or in presence of laurate together with NADPH; under these conditions little degradation of bilirubin was observed. Mesobilirubin was also degraded during uncoupling with perfluorolaurate, whereas biliverdin (which lacks the central methene bridge present in rubins) was unaffected. It is suggested that the CYP ferryl oxygen species abstracts a hydrogen atom from the central methene bridge of bilirubin to generate a radical, which is further dehydrogenated to biliverdin or else binds O₂ and undergoes fragmentation. We conclude that the uncoupled catalytic cycle of cytochrome P450 has properties resembling those of a peroxidase and that bilirubin is rapidly oxidized as a peroxidase substrate. The potential toxicological significance of cytochrome P450 uncoupling is considered.
Schlagwörter	bilirubin ; cytochrome P-450 ; hydrogen ; hydroxylation ; oxygen ; peroxidase ; pharmacology
Sprache	Englisch
Erscheinungsverlauf	2012-0801
Umfang	p. 374-382.
Erscheinungsort	Elsevier Inc.
Dokumenttyp	Artikel
ZDB-ID	208787-x
ISSN	1873-2968 ; 0006-2952
ISSN (online)	1873-2968
ISSN	0006-2952
DOI	10.1016/j.bcp.2012.04.016
Datenquelle	NAL Katalog (AGRICOLA)

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Artikel: Abolition of oxygenase function, retention of NADPH oxidase activity, and emergence of peroxidase activity upon replacement of the axial cysteine-436 ligand by histidine in cytochrome P450 2B4.

Vatsis, Kostas P / Peng, Hwei-Ming / Coon, Minor J

Archives of biochemistry and biophysics

2005 Band 434, Heft 1, Seite(n) 128–138

Abstract: A fundamental aspect of cytochrome P450 function is the role of the strictly conserved axial cysteine ligand, replacement of which by histidine has invariably resulted in mammalian and bacterial preparations devoid of heme. Isolation of the His-436 ... ...

Abstract	A fundamental aspect of cytochrome P450 function is the role of the strictly conserved axial cysteine ligand, replacement of which by histidine has invariably resulted in mammalian and bacterial preparations devoid of heme. Isolation of the His-436 variant of NH2-truncated P450 2B4 partly as the holoenzyme was achieved in the present study by mutagenesis of the I-helix Ala-298 residue to Glu and subsequent conversion of the axial Cys-436 to His. The expressed A298E/C436H double mutant, cloned with a hexahistidine tag, had a molecular mass equivalent to that of the primary structure of His-tagged truncated 2B4 and the sum of the two mutated residues, and contained a heme group which, when released on HPLC, showed a retention time and spectrum identical to those of iron protoporphyrin IX. The absolute spectra of A298E/C436H indicate a change in heme coordination structure from low- to high-spin, and, as expected for a His-ligated hemeprotein, the Soret maximum of the ferrous CO complex is at 422 nm. The double mutant has no oxygenase activity with representative substrates known to undergo transformation by the oxene [(FeO)3+] or peroxo activated oxygen species, but catalyzes significant H2O2 formation that is NADPH- and time-dependent, and directly proportional to the concentration of A298E/C436H in the presence of saturating reductase. Moreover, the catalytic efficiency of A298E/C436H in the H2O2-supported peroxidation of pyrogallol is more than two orders of magnitude greater than that of wild-type 2B4 or the A298E variant. The results unambiguously demonstrate that the proximal thiolate ligand is essential for substrate oxygenation by P450.
Mesh-Begriff(e)	Amino Acid Substitution ; Aryl Hydrocarbon Hydroxylases/chemistry ; Aryl Hydrocarbon Hydroxylases/genetics ; Aryl Hydrocarbon Hydroxylases/metabolism ; Base Sequence ; Catalytic Domain/genetics ; Chromatography, High Pressure Liquid ; Cysteine/chemistry ; Cytochrome P450 Family 2 ; DNA, Complementary/genetics ; Escherichia coli/genetics ; Heme/chemistry ; Histidine/chemistry ; Hydrogen Peroxide/metabolism ; In Vitro Techniques ; Ligands ; Molecular Weight ; Mutagenesis, Site-Directed ; Recombinant Proteins/chemistry ; Recombinant Proteins/genetics ; Recombinant Proteins/metabolism ; Spectrometry, Mass, Electrospray Ionization ; Spectrophotometry
Chemische Substanzen	DNA, Complementary ; Ligands ; Recombinant Proteins ; Heme (42VZT0U6YR) ; Histidine (4QD397987E) ; Hydrogen Peroxide (BBX060AN9V) ; Aryl Hydrocarbon Hydroxylases (EC 1.14.14.1) ; Cytochrome P450 Family 2 (EC 1.14.14.1) ; cytochrome P-450 CYP2B4 (rabbit) (EC 1.14.14.1) ; Cysteine (K848JZ4886)
Sprache	Englisch
Erscheinungsdatum	2005-02-01
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Research Support, U.S. Gov't, P.H.S.
ZDB-ID	523-x
ISSN	1096-0384 ; 0003-9861
ISSN (online)	1096-0384
ISSN	0003-9861
DOI	10.1016/j.abb.2004.10.015
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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