| Electron transfer reactions of high-potential iron-sulfur proteins and c-type cytochromes. | |
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MedLine Citation:
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PMID: 6252957 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Studies of electron transfer by biological oxidation-reduction proteins frequently focus on the interaction of a particular protein with nonphysiological oxidants and/or reductants. This approach, although valuable, is limited by the size and chemistry of the nonphysiological reactants. To further the understanding of biological electron transfer, we have investigated the interaction of two examples of high-potential iron-sulfur proteins (HIPIP's) with mitochondrial cytochrome c (horse heart) and bacterial cytochrome c2 from Rhodospirillum rubrum, Rhodopseudomonas palustris, Rhodopseudomonas capsulata, and Rhodopseudomonas sphaeroides. On the basis of the kinetics of electron transfer between the various HIPIP's and cytochromes, it appears that the interactions are more complex than those observed with nonphysiological reactants. We conclude that (1) specific sites on both the HIPIP's and the cytochromes mediate electron transfer with the effect of ionic strength different from that expected on the basis of the interaction of the various proteins with iron hexacyanides, (2) the interaction of HIPIP with some of the cytochromes investigated is heterogeneous, resulting from at least two possible orientations (cytochrome dependent) for interaction leading to electron transfer, and (3) no long-lived complexes between the HIPIP's and cytochromes are formed due to rapid equilibrium between the two proteins. This last conclusion suggests that the measured second-order rate constant is in fact the product of the association constant (for any HIPIP and a particular cytochrome) and a first-order rate constant reflecting the rate-limiting step leading to products. |
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Authors:
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I A Mizrahi; M A Cusanovich |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Biochemistry Volume: 19 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 1980 Oct |
Date Detail:
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Created Date: 1981-01-16 Completed Date: 1981-01-16 Revised Date: 2007-11-14 |
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: 4733-7 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Chromatium
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metabolism Cytochrome c Group / metabolism* Electron Transport Iron-Sulfur Proteins / metabolism* Kinetics Metalloproteins / metabolism* Oxidation-Reduction Rhodopseudomonas / metabolism |
| Grant Support | |
ID/Acronym/Agency:
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GM 21277/GM/NIGMS NIH HHS; KO4EY0013/EY/NEI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Cytochrome c Group; 0/Iron-Sulfur Proteins; 0/Metalloproteins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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