| Cytochrome b5, cytochrome c, and cytochrome P-450 interactions with NADPH-cytochrome P-450 reductase in phospholipid vesicles. | |
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MedLine Citation:
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PMID: 2847775 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Upon incubation of detergent-solubilized NADPH-cytochrome P-450 reductase and either cytochrome b5 or cytochrome c in the presence of a water-soluble carbodiimide, a 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC), covalently cross-linked complex was formed. The cross-linked derivative was a heterodimer consisting of one molecule each of flavoprotein and cytochrome, and it was purified to 90% or more homogeneity. The binary covalent complex between the flavoprotein and cytochrome b5 was exclusively observed following incubation of all three proteins including NADPH-cytochrome P-450 reductase, cytochrome b5, and cytochrome c in L-alpha-dimyristoylphosphatidylcholine vesicles, and no heterotrimer could be identified. The isolated reductase-cytochrome b5 complex was incapable of covalent binding with cytochrome c in the presence of EDC. No clear band for covalent complex formation between PB-1 and reductase was seen with the present EDC cross-linking technique. More than 90% of the cross-linked cytochrome c in the purified derivative was rapidly reduced upon addition of an NADPH-generating system, whereas approximately 80% of the cross-linked cytochrome b5 was rapidly reduced. These results showed that in the greater part of the complexes, the flavin-mediated pathway for reduction of cytochrome c or cytochrome b5 by pyridine nucleotide was intact. When reconstituted into phospholipid vesicles, the purified amphipathic derivative could hardly reduce exogenously added cytochrome c, cytochrome b5, or PB-1, indicating that the cross-linked cytochrome shields the single-electron-transferring interface of the flavoprotein. These results suggest that the covalent cross-linked derivative is a valid model of the noncovalent functional electron-transfer complex. |
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Authors:
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Y Nisimoto; H Otsuka-Murakami |
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Publication Detail:
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Type: In Vitro; Journal Article |
Journal Detail:
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Title: Biochemistry Volume: 27 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 1988 Aug |
Date Detail:
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Created Date: 1989-01-09 Completed Date: 1989-01-09 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 5869-76 Citation Subset: IM |
Affiliation:
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Department of Biochemistry, Aichi Medical University, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cross-Linking Reagents Cytochrome P-450 Enzyme System / metabolism Cytochrome b Group / metabolism Cytochrome c Group / metabolism Cytochromes b5 Electron Transport Ethyldimethylaminopropyl Carbodiimide Flavin Mononucleotide / metabolism Liposomes Microsomes, Liver / enzymology NADPH-Ferrihemoprotein Reductase / metabolism* Rats |
| Chemical | |
Reg. No./Substance:
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0/Cross-Linking Reagents; 0/Cytochrome b Group; 0/Cytochrome c Group; 0/Liposomes; 146-17-8/Flavin Mononucleotide; 1892-57-5/Ethyldimethylaminopropyl Carbodiimide; 9035-39-6/Cytochromes b5; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.6.2.4/NADPH-Ferrihemoprotein Reductase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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