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Esteves F, Campelo D, Gomes BC, Urban P, Bozonnet S, Lautier T, Rueff J, Truan G, Kranendonk M. The Role of the FMN-Domain of Human Cytochrome P450 Oxidoreductase in Its Promiscuous Interactions With Structurally Diverse Redox Partners. Front Pharmacol 2020; 11:299. [PMID: 32256365 PMCID: PMC7094780 DOI: 10.3389/fphar.2020.00299] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/28/2020] [Indexed: 12/18/2022] Open
Abstract
NADPH cytochrome P450 oxidoreductase (CPR) is the obligatory electron supplier that sustains the activity of microsomal cytochrome P450 (CYP) enzymes. The variant nature of the isoform-specific proximal interface of microsomal CYPs indicates that CPR is capable of multiple degenerated interactions with CYPs for electron transfer, through different binding mechanisms, and which are still not well-understood. Recently, we showed that CPR dynamics allows formation of open conformations that can be sampled by its structurally diverse redox partners in a CYP-isoform dependent manner. To further investigate the role of the CPR FMN-domain in effective binding of CPR to its diverse acceptors and to clarify the underlying molecular mechanisms, five different CPR-FMN-domain random mutant libraries were created. These libraries were screened for mutants with increased activity when combined with specific CYP-isoforms. Seven CPR-FMN-domain mutants were identified, supporting a gain in activity for CYP1A2 (P117H, G144C, A229T), 2A6 (P117L/L125V, G175D, H183Y), or 3A4 (N151D). Effects were evaluated using extended enzyme kinetic analysis, cytochrome b 5 competition, ionic strength effect on CYP activity, and structural analysis. Mutated residues were located either in or adjacent to several acidic amino acid stretches - formerly indicated to be involved in CPR:CYP interactions - or close to two tyrosine residues suggested to be involved in FMN binding. Several of the identified positions co-localize with mutations found in naturally occurring CPR variants that were previously shown to cause CYP-isoform-dependent effects. The mutations do not seem to significantly alter the geometry of the FMN-domain but are likely to cause very subtle alterations leading to improved interaction with a specific CYP. Overall, these data suggest that CYPs interact with CPR using an isoform specific combination of several binding motifs of the FMN-domain.
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Affiliation(s)
- Francisco Esteves
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Diana Campelo
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Bruno Costa Gomes
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Philippe Urban
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Sophie Bozonnet
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Thomas Lautier
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - José Rueff
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Gilles Truan
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Michel Kranendonk
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
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Xia C, Shen AL, Duangkaew P, Kotewong R, Rongnoparut P, Feix J, Kim JJP. Structural and Functional Studies of the Membrane-Binding Domain of NADPH-Cytochrome P450 Oxidoreductase. Biochemistry 2019; 58:2408-2418. [PMID: 31009206 PMCID: PMC6873807 DOI: 10.1021/acs.biochem.9b00130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR), the essential flavoprotein of the microsomal cytochrome P450 monooxygenase system, is anchored in the phospholipid bilayer by its amino-terminal membrane-binding domain (MBD), which is necessary for efficient electron transfer to cytochrome P450. Although crystallographic and kinetic studies have established the structure of the soluble catalytic domain and the role of conformational motions in the control of electron transfer, the role of the MBD is largely unknown. We examined the role of the MBD in P450 catalysis through studies of amino-terminal deletion mutants and site-directed spin labeling. We show that the MBD spans the membrane and present a model for the orientation of CYPOR on the membrane capable of forming a complex with cytochrome P450. EPR power saturation measurements of CYPOR mutants in liposomes containing a lipid/Ni(II) chelate identified a region of the soluble domain interacting with the membrane. The deletion of more than 29 residues from the N-terminus of CYPOR decreases cytochrome P450 activity concomitant with alterations in electrophoretic mobility and an increased resistance to protease digestion. The altered kinetic properties of these mutants are consistent with electron transfer through random collisions rather than via formation of a stable CYPOR-P450 complex. Purified MBD binds weakly to cytochrome P450, suggesting that other interactions are also required for CYPOR-P450 complex formation. We propose that the MBD and flexible tether region of CYPOR, residues 51-63, play an important role in facilitating the movement of the soluble domain relative to the membrane and in promoting multiple orientations that permit specific interactions of CYPOR with its varied partners.
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Affiliation(s)
- Chuanwu Xia
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
| | - Anna L Shen
- McArdle Laboratory for Cancer Research , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Panida Duangkaew
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Rattanawadee Kotewong
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Pornpimol Rongnoparut
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Jimmy Feix
- Department of Biophysics , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
| | - Jung-Ja P Kim
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
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Miyamoto M, Yamashita T, Yasuhara Y, Hayasaki A, Hosokawa Y, Tsujino H, Uno T. Membrane Anchor of Cytochrome P450 Reductase Suppresses the Uncoupling of Cytochrome P450. Chem Pharm Bull (Tokyo) 2015; 63:286-94. [DOI: 10.1248/cpb.c15-00034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Taku Yamashita
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women’s University
| | - Yuki Yasuhara
- Graduate School of Pharmaceutical Sciences, Osaka University
| | | | - Yukari Hosokawa
- Graduate School of Pharmaceutical Sciences, Osaka University
| | | | - Tadayuki Uno
- Graduate School of Pharmaceutical Sciences, Osaka University
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4
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Probing the transmembrane structure and dynamics of microsomal NADPH-cytochrome P450 oxidoreductase by solid-state NMR. Biophys J 2014; 106:2126-33. [PMID: 24853741 DOI: 10.1016/j.bpj.2014.03.051] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/02/2014] [Accepted: 03/19/2014] [Indexed: 10/25/2022] Open
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR) is an essential redox partner of the cytochrome P450 (cyt P450) superfamily of metabolic enzymes. In the endoplasmic reticulum of liver cells, such enzymes metabolize ~75% of the pharmaceuticals in use today. It is known that the transmembrane domain of CYPOR plays a crucial role in aiding the formation of a complex between CYPOR and cyt P450. Here we present the transmembrane structure, topology, and dynamics of the FMN binding domain of CYPOR in a native membrane-like environment. Our solid-state NMR results reveal that the N-terminal transmembrane domain of CYPOR adopts an α-helical conformation in the lipid membrane environment. Most notably, we also show that the transmembrane helix is tilted ~13° from the lipid bilayer normal, and exhibits motions on a submillisecond timescale including rotational diffusion of the whole helix and fluctuation of the helical director axis. The approaches and the information reported in this study would enable further investigations on the structure and dynamics of the full-length NADPH-cytochrome P450 oxidoreductase and its interaction with other membrane proteins in a membrane environment.
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Gideon DA, Kumari R, Lynn AM, Manoj KM. What is the Functional Role of N-terminal Transmembrane Helices in the Metabolism Mediated by Liver Microsomal Cytochrome P450 and its Reductase? Cell Biochem Biophys 2012; 63:35-45. [PMID: 22302675 DOI: 10.1007/s12013-012-9339-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We sought to clarify on the hitherto unresolved role of N-terminal transmembrane segments (TMS) of cytochrome P450 (CYP) and its' reductase (CPR) in protein interaction/catalysis. TMS analyses show little evolutionary conservation in CYPs. The conserved CPR's TMS poses limited scope for predictable/consistent hetero-recognition with the wide bevy of CYPs' TMS, as evident from preliminary analyses and TMhit server predictions for inter-helical binding. Further, experimentations with four different CPR preparations (preps) and two liver microsomal CYPs (2C9 and 2E1) shows that the hydroxylated product formation rate is not quantitatively correlated to the extent of integrity of the CPR N-terms. Incorporation of cytochrome b (5) in some reactions afforded similar rates while employing either fully intact or partially intact CPR. A survey of literature shows that liver microsomal CYPs function quite well even without the TMS or with significantly altered TMS. These observations negate the hypothesis that N-term TMS of CPR or CYP is obligatory for CYP-CPR interaction and catalysis. Also, in CYP2E1-mediated hydroxylation of para-nitrophenol, the extent of intactness or truncation did not significantly affect the CPR preps' catalytic role at very low or high substrate concentrations. To interpret these results, we draw support from recently published research on reduced nicotinamide adenide dinucleotide phosphate oxidase (Takac et al., J Biol Chem, 286:13304-13313, 2011) and from our pertinent earlier works. We infer that CPR' free TMS segment could alter the diffusible reactive oxygen species' dynamics in the microenvironment, thereby altering the reaction outcome. Based on the evidence, we conclude that TMS merely facilitates "interaction/catalysis" by anchoring the CYP and CPR in the lipid interface.
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Affiliation(s)
- Daniel Andrew Gideon
- Heme & Flavo Proteins Laboratory, Center for Biomedical Research, VIT University, #204, Vellore, 632014, Tamil Nadu, India
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Laursen T, Jensen K, Møller BL. Conformational changes of the NADPH-dependent cytochrome P450 reductase in the course of electron transfer to cytochromes P450. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:132-8. [PMID: 20624491 DOI: 10.1016/j.bbapap.2010.07.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/09/2010] [Accepted: 07/01/2010] [Indexed: 01/18/2023]
Abstract
The NADPH-dependent cytochrome P450 reductase (CPR) is a key electron donor to eucaryotic cytochromes P450 (CYPs). CPR shuttles electrons from NADPH through the FAD and FMN-coenzymes into the iron of the prosthetic heme-group of the CYP. In the course of these electron transfer reactions, CPR undergoes large conformational changes. This mini-review discusses the new evidence provided for such conformational changes involving a combination of a "swinging" and "rotating" model and highlights the molecular mechanisms by which formation of these conformations are controlled and thereby enables CPR to serve as an effective electron transferring "nano-machine".
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Affiliation(s)
- Tomas Laursen
- Plant Biochemistry Laboratory, Department of Plant Biology and Biotechnology, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
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7
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Black SD, Coon MJ. P-450 cytochromes: structure and function. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 60:35-87. [PMID: 3310532 DOI: 10.1002/9780470123065.ch2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- S D Black
- Division of Medicinal Chemistry and Pharmacognosy, Ohio State University, Columbus
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Nikfarjam L, Izumi S, Yamazaki T, Kominami S. The interaction of cytochrome P450 17α with NADPH-cytochrome P450 reductase, investigated using chemical modification and MALDI-TOF mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:1126-31. [PMID: 16713412 DOI: 10.1016/j.bbapap.2006.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 03/22/2006] [Accepted: 04/01/2006] [Indexed: 11/28/2022]
Abstract
The lysine residues of guinea pig P450 17alpha were acetylated by acetic anhydride in the absence and presence of NADPH cytochrome P450 reductase (CPR). Eight acetylated peptides were identified in the MALDI-TOF mass spectra of the tryptic fragments from the P450 acetylated without CPR in the limited reaction time of 15 min at ice temperature. The presence of CPR during the acetylation of P450 17alpha prevented double acetylations at K326 and K327 in the J-helix. The activity of P450 17alpha was decreased to 35% by the acetylation, but almost no inactivation was detected in the P450 after acetylation in the presence of CPR. This protection from inactivation shows the importance of K326 and/or K327 in the J-helix of P450 17alpha in the interaction between the two enzymes. Our results provided the first experimental evidence for the importance of the J-helix of P450 in the interaction with CPR. The interaction of P450 17alpha with CPR on the membrane is discussed based on the results of this study, which used molecular modeling.
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Affiliation(s)
- Laleh Nikfarjam
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashihiroshima 739-8528, Japan
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Bonina TA, Gilep AA, Estabrook RW, Usanov SA. Engineering of proteolytically stable NADPH-cytochrome P450 reductase. BIOCHEMISTRY (MOSCOW) 2005; 70:357-65. [PMID: 15823091 DOI: 10.1007/s10541-005-0122-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
NADPH-cytochrome P450 reductase (CPR) is a membrane-bound flavoprotein that interacts with the membrane via its N-terminal hydrophobic sequence (residues 1-56). CPR is the main electron transfer component of hydroxylation reactions catalyzed by microsomal cytochrome P450s. The membrane-bound hydrophobic domain of NADPH-cytochrome P450 reductase is easily removed during limited proteolysis and is the subject of spontaneous digestion of membrane-binding fragment at the site Lys56-Ile57 by intracellular trypsin-like proteases that makes the flavoprotein very unstable during purification or expression in E. coli. The removal of the N-terminal hydrophobic sequence of NADPH-cytochrome P450 reductase results in loss of the ability of the flavoprotein to interact and transfer electrons to cytochrome P450. In the present work, by replacement of the lysine residue (Lys56) with Gln using site directed mutagenesis, we prepared the full-length flavoprotein mutant Lys56Gln stable to spontaneous proteolysis but possessing spectral and catalytic properties of the wild type flavoprotein. Limited proteolysis with trypsin and protease from Staphylococcus aureus of highly purified and membrane-bound Lys56Gln mutant of the flavoprotein as well as wild type NADPH-cytochrome P450 reductase allowed localization of some amino acids of the linker fragment of NADPH-cytochrome P450 reductase relative to the membrane. During prolong incubation or with increased trypsin ratio, the mutant form showed an alternative limited proteolysis pattern, indicating the partial accessibility of another site. Nevertheless, the membrane-bound mutant form is stable to trypsinolysis. Truncated forms of the flavoprotein (residues 46-676 of the mutant or 57-676 of wild type NADPH-cytochrome P450 reductase) are unable to transfer electrons to cytochrome P450c17 or P4503A4, confirming the importance of the N-terminal sequence for catalysis. Based on the results obtained in the present work, we suggest a scheme of structural topology of the N-terminal hydrophobic sequence of NADPH-cytochrome P450 reductase in the membrane.
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Affiliation(s)
- T A Bonina
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk 220141, Belarus
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10
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James MO, Boyle SM. Cytochromes P450 in crustacea. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1998; 121:157-72. [PMID: 9972457 DOI: 10.1016/s0742-8413(98)10036-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Since the last review of this topic, further insight has been gained into the presence and functions of cytochrome P450 proteins in the hepatopancreas and other organs of aquatic crustacean species, although progress has been slow relative to the advances in other species. Recent studies with several lobster, shrimp, crab and crayfish species suggest that cytochromes P450 in the 2 and 3 families are the most abundant forms in hepatopancreas microsomes. Substrates normally metabolized by CYP2 and CYP3 family members are monooxygenated more rapidly by crustacea than substrates normally metabolized by CYP1 family enzymes, e.g. erythromycin, testosterone and aminopyrine are much more rapidly monooxygenated than ethoxyresorufin. Some progress has been made in cloning and sequencing crustacean P450 forms. CYP2L1 and CYP2L2 cDNA sequences have been cloned from spiny lobster hepatopancreas libraries, and there was evidence for at least two more cytochromes P450 in spiny lobster hepatopancreas. An area of continued interest, but of no consensus or general findings, relates to the presence and inducibility of CYP1 family members in crustacea. Some studies indicate weak induction of total cytochrome P450 and increased turnover of substrates normally associated with CYP1, while others show no effect of the classic inducers that act at the Ah receptor in vertebrates. A few studies of the roles of cytochromes P450 in the biosynthesis and degradation of steroids, including ecdysteroids, have been published. Further studies are needed to understand the regulation and normal function of the crustacean cytochromes P450.
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Affiliation(s)
- M O James
- Department of Medicinal Chemistry, College of Pharmacy and the Whitney Marine Laboratory, University of Florida, Gainesville 32610-0485, USA
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11
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Van den Broek PJ, Barroso M, Lechner MC. Critical amino-terminal segments in insertion of rat liver cytochrome P450 3A1 into the endoplasmic reticulum membrane. EXPERIENTIA 1996; 52:851-5. [PMID: 8841512 DOI: 10.1007/bf01938869] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An in vitro transcription-translation assay was used to study the membrane topology of rat liver cytochrome P450 3A1. N-terminus deletion mutants were constructed to assess the importance of N-terminal regions in the stable incorporation of the protein into the microsomal membranes. Wild-type nascent cytochrome P450 bound to microsomes as an integral membrane protein through its hydrophobic N-terminal segments, uncleaved by signal peptidase. Deletion of the most N-terminal hydrophobic segment (positions 7-26) had a dramatic effect on endoplasmic reticulum membrane integration. Confirming the essential role of this stretch in P450 3A1 membrane targeting, proteolysis-resistant membrane-associated peptides were observed in all the in vitro translated mutants containing that segment. It is concluded that the membrane topogenesis of P450 3A1 is determined mainly by the amino-terminal hydrophobic segment.
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Affiliation(s)
- P J Van den Broek
- Department of Biochemistry, Gulbenkian Institute of Science, Oeiras, Portugal
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12
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Goeptar AR, Scheerens H, Vermeulen NP. Oxygen and xenobiotic reductase activities of cytochrome P450. Crit Rev Toxicol 1995; 25:25-65. [PMID: 7734059 DOI: 10.3109/10408449509089886] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The oxygen reductase and xenobiotic reductase activities of cytochrome P450 (P450) are reviewed. During the oxygen reductase activity of P450, molecular oxygen is reduced to superoxide anion radicals (O2-.) most likely by autooxidation of a P450 ferric-dioxyanion complex. The formation of reactive oxygen species (O2-., hydrogen peroxide, and, notably, hydroxyl free radicals) presents a potential toxication pathway, particularly when effective means of detoxication are lacking. Under anaerobic conditions, P450 may also be involved in the reduction of xenobiotics. During the xenobiotic reductase activity of P450, xenobiotics are reduced by the ferrous xenobiotic complex. After xenobiotic reduction by P450, xenobiotic free radicals are formed that are often capable of reacting directly with tissue macromolecules. Unfortunately, the compounds that are reductively activated by P450 have little structural similarity. The precise molecular mechanism underlying the xenobiotic reductase activity of P450 is, therefore, not yet fully understood. Moreover, description of the molecular mechanisms of xenobiotic and oxygen reduction reactions by P450 is limited by the lack of knowledge of the three-dimensional (3D) structure of the mammalian P450 proteins.
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Affiliation(s)
- A R Goeptar
- Leiden/Amsterdam Center for Drug Research, Vrije Universiteit, The Netherlands
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Norris PJ, Hardwick JP, Emson PC. Localization of NADPH cytochrome P450 oxidoreductase in rat brain by immunohistochemistry and in situ hybridization and a comparison with the distribution of neuronal NADPH-diaphorase staining. Neuroscience 1994; 61:331-50. [PMID: 7969913 DOI: 10.1016/0306-4522(94)90235-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An antibody to cytochrome P450 oxidoreductase, purified from rat liver, has been used for the immunohistochemical localization of cytochrome P450 oxidoreductase-like immunoreactivity in the rat central nervous system. The distribution of this immunoreactivity has been confirmed using in situ hybridization with specific cytochrome P450 oxidoreductase antisense DNA probes. Cytochrome P450 oxidoreductase immunoreactivity was detected in neurons and was found in some glial populations. Immunoreactivity and in situ messenger RNA signals were present in many forebrain areas including the olfactory bulb, in the cerebral cortex, caudate-putamen, globus pallidus, hypothalamus, thalamus and hippocampus. Cytochrome P450 oxidoreductase was also detected in the nucleus of the posterior commissure, superior colliculus, intermediate gray layer, periaqueductal gray and in the molecular, Purkinje and granular layers of the cerebellum. In the brain stem, cytochrome P450 oxidoreductase was detected in the substantia nigra, nucleus locus coeruleus and raphe nucleus. Western blotting studies revealed the brain immunoreactive protein has a mol. wt of approximately 72,000, as reported for cytochrome P450 oxidoreductase purified from rat brain microsomes. The distribution of cytochrome P450 oxidoreductase immunoreactivity was compared with the distribution of cells exhibiting NADPH diaphorase activity, which has been established as a histochemical marker for neuronal nitric oxide synthase, an enzyme which has a C-terminus with some structural similarity with cytochrome P450 oxidoreductase and catalyses a complex reaction resulting in the synthesis of nitric oxide from arginine. In general, cytochrome P450 oxidoreductase immunoreactivity and nitric oxide synthase diaphorase activity did not co-localize; however, some neuronal populations did express nitric oxide synthase and exhibit cytochrome P450 oxidoreductase immunoreactivity. Results of immunohistochemistry and in situ hybridization experiments suggest cytochrome P450 oxidoreductase is widespread in the rat central nervous system. The distribution pattern of cytochrome P450 oxidoreductase did not match with those of any one neurotransmitter; however, it did coincide with some brain regions known to harbour central catecholaminergic neurons. The general distribution of cytochrome P450 oxidoreductase was similar to the distribution reported for haeme oxygenase 2 and several cytochrome P450 enzymes. It is possible that malfunctions in cytochrome P450 enzyme systems and/or the haeme oxygenase 2 pathways, both of which involve cytochrome P450 oxidoreductase, may have implications in neurodegenerative diseases.
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Affiliation(s)
- P J Norris
- Department of Neurobiology, AFRC Babraham Institute, Cambridge, U.K
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14
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Williams DA, Purohit A, Reed MJ. Immunochemical specificity of placental NADPH cytochrome c (P-450) reductase in neoplastic and non-neoplastic human tissue. J Steroid Biochem Mol Biol 1992; 43:515-22. [PMID: 1419886 DOI: 10.1016/0960-0760(92)90238-e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
NADPH cytochrome c (P-450) reductase was purified from human placental microsomes using a combination of affinity and gel filtration chromatography. Affinity chromatography using agarose-hexane-adenosine 2'5 diphosphate resulted in two protein bands being detected by SDS-PAGE of approximate MwS 68 and 75 kDa. Fractions containing the two proteins were pooled, and then resolved using Sephacryl S-200. Both of the purified proteins displayed enzyme activity, measured by their ability to reduce cytochrome c. The 75 kDa protein obtained was used to immunize three female New Zealand white rabbits. The IgG fraction was partly purified from rabbit sera which suppressed placental microsomal NADPH cytochrome c reductase activity by > 80% using 33% ammonium sulphate. The procured antibody suppressed androstenedione aromatase activity in microsomal preparations of human placental and breast adipose tissue, and NADPH cytochrome c reductase activity in prostate (benign and malignant), MDA-MB-231 breast cancer cells, breast adipose, Hep G2 hepatoma cells and placental microsomal preparations. The extent of NADPH cytochrome c reductase inhibition varied in the order of malignant prostate < benign prostate < MDA < breast adipose < Hep G2 < placenta. The results suggest that human placental NADPH cytochrome c (P-450) reductase shares common antigenic epitopes pertinent to its capability of reducing cytochrome c in all of the above-mentioned tissues. In attempting to associate possible changes in NADPH cytochrome c reductase activity imposed by neoplasia to the obtained immunochemical cross reactivity and enzyme activity results, it was noted that microsomes obtained from MDA cells exhibited enzyme activity significantly less than that of breast adipose microsomes (1.6 and 8.1 nmol/min/mg protein, respectively) and by comparison showed 6% less homology towards the placental antibody. The results obtained for benign and malignant prostate showed no significant difference between the neoplastic states as adjudged by enzyme activity and immunochemical assays.
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Affiliation(s)
- D A Williams
- Unit of Metabolic Medicine, St Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, University of London, England
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Abstract
In recent years there has been increasing interest in antimutagenesis, and studies have been done using both prokaryotic and eukaryotic systems. In eukaryotic systems the first studies were performed with different strains of Schizosaccharomyces pombe. In particular, caffeine and L-methionine were investigated. Different strains of Saccharomyces cerevisiae were employed in studies of a wide variety of compounds, including acridine, saccharin, salts, tumor promoters and co-carcinogens. Strain D7 was widely employed and antimutagenic activity of spermine, chlorophyllin, cobaltous chloride and fermented milk is reported.
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Affiliation(s)
- G Bronzetti
- Istituto di Mutagenesi e Differenziamento, CNR, Pisa, Italy
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Shen S, Strobel HW. The role of cytochrome P450 lysine residues in the interaction between cytochrome P450IA1 and NADPH-cytochrome P450 reductase. Arch Biochem Biophys 1992; 294:83-90. [PMID: 1550361 DOI: 10.1016/0003-9861(92)90140-r] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cytochrome P450IA1 (purified from hepatic microsomes of beta-naphthoflavone-treated rats) has been covalently modified with the lysine-modifying reagent acetic anhydride. Different levels of lysine residue modification in cytochrome P450IA1 can be achieved by varying the concentration of acetic anhydride. Modification of lysine residues in P450IA1 greatly inhibits the interaction of P450IA1 with NADPH-cytochrome P450 reductase. Modification of 1.0 and 3.3 mol lysine residues per mole P450IA1 resulted in 30 and 95% decreases, respectively, in 7-ethoxycoumarin hydroxylation by a reconstituted P450IA1/reductase complex. However, modification of 3.3 mol lysine residues per mole P450IA1 decreased only cumene hydroperoxide-supported P450-dependent 7-ethoxycoumarin hydroxylation by 30%. Spectral and fluorescence studies showed no indication of global conformational change of P450IA1 even with up to 8.8 mol lysine residues modified per mole P450IA1. These data suggest that at least three lysine residues in P450IA1 may be involved in the interaction with reductase. Identification of lysine residues in P450IA1 possibly involved in this interaction was carried out by [14C]acetic anhydride modification, trypsin digestion, HPLC separation, and amino acid sequencing. The lysine residue candidates identified in this manner were K97, K271, K279, and K407.
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Affiliation(s)
- S Shen
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77225
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17
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Nadler SG, Strobel HW. Identification and characterization of an NADPH-cytochrome P450 reductase derived peptide involved in binding to cytochrome P450. Arch Biochem Biophys 1991; 290:277-84. [PMID: 1929397 DOI: 10.1016/0003-9861(91)90542-q] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The amino acids of cytochrome P450 reductase involved in the interaction with cytochrome P450 were identified with a differential labeling technique. The water-soluble carbodiimide EDC (1-ethyl-3-[3- (dimethylamino)propyl]-carbodiimide) was used with the nucleophile methylamine to modify carboxyl residues. When the modification was performed in the presence of cytochrome P450, there was no inhibition in the ability of the modified reductase to bind to cytochrome P450. However, subsequent modification of the reductase in the absence of cytochrome P450 caused a fourfold increase in the Km and an 80% decrease in kcat/Km (relative to the reductase modified in the first step), for the interaction with cytochrome P450. These effects are attributed to the modification of approximately 3.2 mol of carboxyl residues per mole of reductase. Tryptic peptides generated from the modified reductase were purified by reverse phase high-performance liquid chromatography and characterized. Amino acid sequencing and analysis suggest that the peptide which contains approximately 40% of the labeled carboxyl residues corresponds to amino acid residues 109-130 of rat liver NADPH-cytochrome P450 reductase. One or more of the seven carboxyl containing amino acids within this peptide is presumably involved in the interaction with cytochrome P450.
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Affiliation(s)
- S G Nadler
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77025
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18
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Isolation and characterization of the alkane-inducible NADPH-cytochrome P-450 oxidoreductase gene from Candida tropicalis. Identification of invariant residues within similar amino acid sequences of divergent flavoproteins. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)46240-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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19
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Kurzban GP, Howarth J, Palmer G, Strobel HW. NADPH-cytochrome P-450 reductase. Physical properties and redox behavior in the absence of the FAD moiety. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38341-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Bellino FL, Holben L. Placental estrogen synthetase (aromatase): evidence for phosphatase-dependent inactivation. Biochem Biophys Res Commun 1989; 162:498-504. [PMID: 2546553 DOI: 10.1016/0006-291x(89)92025-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The acute regulation of estrogen synthetase (aromatase), the cytochrome P450 enzyme system responsible for estrogen production, is not well explored. We report here that aromatase, but not NADPH-cytochrome c (P450) reductase, activity from human term placental microsomes decreased when incubated in phosphate-free buffer at 37 degrees C. Aromatase activity was stabilized by phosphate buffer or by the phosphatase inhibitors tartaric acid or EDTA, but not NaF, in phosphate-free buffer. Alkaline phosphatase also inhibited aromatase in phosphate-free buffer relative to phosphate buffer, but the inactivation appears to be due primarily to proteolytic solubilization of NADPH-cytochrome c reductase from the microsomes by proteases within the alkaline phosphatase preparation. Based on these data, we suggest that the cytochrome P450 component of aromatase may be regulated acutely by phosphorylation-dependent processes.
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Affiliation(s)
- F L Bellino
- Dept. of Biological Sciences, SUNY/Buffalo 14260
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21
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22
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Strobel HW, Nadler SG, Nelson DR. Cytochrome P-450: cytochrome P-450 reductase interactions. Drug Metab Rev 1989; 20:519-33. [PMID: 2680395 DOI: 10.3109/03602538909103558] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- H W Strobel
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77225
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23
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Nadler SG, Strobel HW. Role of electrostatic interactions in the reaction of NADPH-cytochrome P-450 reductase with cytochromes P-450. Arch Biochem Biophys 1988; 261:418-29. [PMID: 3128173 DOI: 10.1016/0003-9861(88)90358-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Chemical modification of cytochrome P-450 reductase was used to determine the involvement of charged amino acids in the interaction between the reductase and two forms of cytochrome P-450. Acetylation of 11 lysine residues of the reductase with acetic anhydride yielded a 20-40% decrease in the apparent Km of the reductase for cytochrome P-450b or cytochrome P-450c using either 7-ethoxycoumarin or benzphetamine as substrates. A 20-45% decrease in the Vmax was observed except for cytochrome P-450b with 7-ethoxycoumarin as substrate, where there was a 27% increase. Modification of carboxyl groups on the reductase with 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide (EDC) and methylamine, glycine methyl ester, or taurine as nucleophiles inhibited the interaction with the cytochromes P-450. We were able to modify 4.0, 7.9, and 5.9 carboxyl groups using methylamine, glycine methyl ester, or taurine, respectively. The apparent Km for cytochrome P-450c or cytochrome P-450b was increased 1.3- to 5.2-fold in a reconstituted monooxygenase assay with 7-ethoxycoumarin or benzphetamine as substrate. There were varied effects on the Vmax. There was no significant change in the conformation of the reductase upon chemical modification with either acetic anhydride or EDC. These results strongly suggest that electrostatic interactions as well as steric constraints play a role in the binding and electron transfer step(s) between the reductase and cytochrome P-450.
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Affiliation(s)
- S G Nadler
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77025
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24
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Işcan MY, Arinç E. Comparison of highly purified sheep liver and lung NADPH-cytochrome P-450 reductases by the analysis of kinetic and catalytic properties. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1988; 20:1189-96. [PMID: 3150357 DOI: 10.1016/0020-711x(88)90218-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. Reductase was purified to electrophoretic homogeneity from sheep liver and lung microsomes. The specific activity of both enzymes ranged from 55 to 66 mumol cytochrome c reduced/min/mg protein. 2. Liver and lung reductases appeared to have similar kinetic and spectral properties. Km (NADPH) and Km (cytochrome c) values were calculated to be 14.3 +/- 1.23 microM and 22.2 +/- 2.78 microM for liver and 11.1 +/- 0.70 microM and 20.0 +/- 2.15 microM for lung reductase, respectively. Kinetic studies showed that cytochrome c can bind the oxidized form of the enzyme as well as its reduced form and both reductases operated through a ping-pong type mechanism. 3. These reductases cannot be distinguished on the basis of monomer molecular weights (Mr 78,000) except that the liver reductase was found to be more susceptible to proteolytic attack. 4. Both reductases supported aniline 4-hydroxylation and ethylmorphine N-demethylation reactions to the same extent in the reconstituted systems. However, sheep lung reductase appeared only 36.5 and 14.8% as effective in catalyzing benzo[a]pyrene reaction as an equivalent amount of reductase from liver in the presence of liver cytochrome P-450 and 3MC-treated rat liver cytochrome P-448, respectively.
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Affiliation(s)
- M Y Işcan
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
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25
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Kominami S, Ikushiro S, Takemori S. Two modes of binding of adrenal NADPH-cytochrome P-450 reductase to liposomal membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 905:143-50. [PMID: 3118953 DOI: 10.1016/0005-2736(87)90018-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
NADPH-cytochrome P-450 reductase, purified from bovine adrenocortical microsomes, was shown to bind in two different modes to liposomal membranes composed of phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine at a molar ratio of 5:3:1. As demonstrated by Ficoll density gradient centrifugation and HPLC gel filtration, the cholate dialysis method made the reductase bind tightly to the liposomal membranes, while the incubation with the preformed vesicles made the reductase bind loosely to the membranes. From the experiments of electron transfer to P-450C21 residing at the other vesicles, the loosely bound reductase was found to be transferable between the vesicles, whereas the tightly bound reductase was not readily transferred. The rates of the binding and the release of the loosely bound reductase to and from the membranes were measured with the stopped-flow method by observing the reduction of P-450C21 embedded in the vesicles. These kinetic studies showed that the rate-limiting step of the reductase transfer between the vesicles was the release of the reductase from the membranes. The reductase in both binding modes well supported the steroid 21-hydroxylase activity.
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Affiliation(s)
- S Kominami
- Faculty of Integrated Arts and Sciences, Hiroshima University, Japan
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26
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Kurzban GP, Strobel HW. Preparation and characterization of FAD-dependent NADPH-cytochrome P-450 reductase. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)57476-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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27
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Strobel HW, Fang WF, Takazawa RS, Stralka DJ, Newaz SN, Kurzban GP, Nelson DR, Beyer RS. Cytochromes P-450 and the activation and inactivation of mutagens and carcinogens. BASIC LIFE SCIENCES 1986; 39:61-71. [PMID: 3094496 DOI: 10.1007/978-1-4684-5182-5_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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28
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Vincent DR, Terriere LC. Characterization of NADPH-cytochrome reductase from house flies (Musca domestica, L.) susceptible and resistant to insecticides, and the blow fly (Phormia regina, meigen). ACTA ACUST UNITED AC 1985. [DOI: 10.1016/0020-1790(85)90018-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Haniu M, Iyanagi T, Legesse K, Shively JE. Structural analysis of NADPH-cytochrome P-450 reductase from porcine hepatic microsomes. Sequences of proteolytic fragments, cysteine-containing peptides, and a NADPH-protected cysteine peptide. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)89802-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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Kominami S, Hara H, Ogishima T, Takemori S. Interaction between cytochrome P-450 (P-450C21) and NADPH-cytochrome P-450 reductase from adrenocortical microsomes in a reconstituted system. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43247-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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31
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Feyereisen R, Vincent D. Characterization of antibodies to house fly NADPH-cytochrome reductase. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0020-1790(84)90025-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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32
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Kensil CR, Hediger MA, Ozols J, Strittmatter P. Isolation and partial characterization of the NH2-terminal membrane-binding domain of NADH-cytochrome b5 reductase. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43913-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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33
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Williams DE, Becker RR, Potter DW, Guengerich FP, Buhler DR. Purification and comparative properties of NADPH-cytochrome P-450 reductase from rat and rainbow trout: differences in temperature optima between reconstituted and microsomal trout enzymes. Arch Biochem Biophys 1983; 225:55-65. [PMID: 6412633 DOI: 10.1016/0003-9861(83)90006-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
NADPH-cytochrome P-450 reductase has been purified to apparent homogeneity from liver microsomes of beta-naphthoflavone-treated rats and rainbow trout. The apparent monomeric molecular weights were 75,000 and 77,000 for the rat and trout, respectively. Differences in amino acid composition were observed, particularly for lysine, glycine, threonine, and tyrosine. Analysis of the flavin composition showed that there were 0.97 mol of FAD and 0.92 mol of FMN per mol of rat reductase, whereas the values for the trout enzyme were 1.06 and 0.76 for FAD and FMN, respectively. Trout NADPH-cytochrome c reductase was inhibited by anti-rat antibody, but not to the same extent as was the rat enzyme. No precipitin lines between the trout reductase and rat antibody were observed on Ouchterlony plates. Peptide patterns, on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, following limited proteolysis were also markedly different. The trout enzyme was as effective, catalytically, as the rat enzyme in a reconstituted system that contained purified rat cytochrome P-448 and lipid. Comparison of ethoxyresorufin-O-deethylase temperature profiles with various combinations of purified trout and rat P-448, reductase, and lipid, in membranous and nonmembranous reconstitution systems, demonstrated that the lower temperature optimum in trout microsomes could only be reproduced when all three trout components were incorporated into liposomes. These results suggest that it is the structural organization of the mixed-function oxidase enzymes and lipid within trout microsomes which were responsible for the lower temperature optimum compared to rat.
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34
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Tsuchida S, Sato K. Purification of detergent-solubilized form and membrane-binding domain of rat gamma-glutamyltransferase by immuno-affinity and hydrophobic chromatography. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 756:341-8. [PMID: 6131698 DOI: 10.1016/0304-4165(83)90343-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A new method to purify papain- or detergent-solubilized form (papain or detergent form) of gamma-glutamyltransferase from rat hepatomas as well as from rat kidney by immuno-affinity column chromatography is presented. The antibody-column was prepared by coupling the anti-kidney papain form antibody, which had been purified by using a kidney papain form-Sepharose column, to CNBr-activated Sepharose 4B. The enzyme bound to the antibody-column was eluted with 0.04 M NH4OH. By this method, detergent forms were purified 300 and 1600-fold in approx. 50% yields from rat kidney and rat ascites hepatoma AH 13, respectively, and the papain form was also purified 16 000-fold in a similar yield from primary hepatoma which has a very low activity of this enzyme. Preparations thus obtained apparently did not contain any peptide other than heavy and light subunit peptides of this enzyme on SDS-polyacrylamide gel electrophoresis. The detergent form of kidney enzyme was preferentially absorbed to a hydrophobic column of aminooctyl-Sepharose, while the papain form was not, suggesting that the detergent form might be adsorbed to the column through hydrophobic interaction of the membrane-binding domain. The domain peptide was also purified by the hydrophobic column after release from the detergent form by papain treatment. The molecular weight of the peptide was estimated to be about 16 000 on SDS-polyacrylamide gel electrophoresis. On double immunodiffusion, the domain peptide reacted with anti-detergent form antibody but not with anti-papain form antibody. The domain-specific antibody was also purified from the anti-detergent form antibody.
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35
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36
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37
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Structural features of liver microsomal NADPH-cytochrome P-450 reductase. Hydrophobic domain, hydrophilic domain, and connecting region. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)83868-1] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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