| Energy requirements for two aspects of phospholipid metabolism in mammalian brain. | |
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MedLine Citation:
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PMID: 9761729 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Previous estimates have placed the energy requirements of total phospholipid metabolism in mammalian brain at 2% or less of total ATP consumption. This low estimate was consistent with the very long half-lives (up to days) reported for fatty acids esterified within phospholipids. However, using an approach featuring analysis of brain acyl-CoA, which takes into account dilution of the precursor acyl-CoA pool by recycling of fatty acids, we reported that half-lives of fatty acids in phospholipids are some 100 times shorter (min-h) than previously thought. Based on these new estimates of short half-lives, palmitic acid and arachidonic acid were used as prototype fatty acids to calculate energy consumption by fatty acid recycling at the sn-1 and sn-2 positions of brain phospholipids. We calculated that the energy requirements for reacylation of fatty acids into lysophospholipids are 5% of net brain ATP consumption. We also calculated ATP requirements for maintaining asymmetry of the aminophospholipids, phosphatidylserine and phosphatidylethanolamine across brain membrane bilayers. This asymmetry is maintained by a translocase at a stoichiometry of 1 mol of ATP per mol of phospholipid transferred in either direction across the membrane. The energy cost of maintaining membrane bilayer asymmetry of aminophospholipids at steady-state was calculated to be 8% of total ATP consumed. Taken together, deacylation-reacylation and maintenance of membrane asymmetry of phosphatidylserine and phosphatidylethanolamine require about 13% of ATP consumed by brain as a whole. This is a lower limit for energy consumption by processes involving phospholipids, as other processes, including phosphorylation of polyphosphoinositides and de novo phospholipid biosynthesis, were not considered. |
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Authors:
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A D Purdon; S I Rapoport |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Biochemical journal Volume: 335 ( Pt 2) ISSN: 0264-6021 ISO Abbreviation: Biochem. J. Publication Date: 1998 Oct |
Date Detail:
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Created Date: 1998-12-22 Completed Date: 1998-12-22 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 2984726R Medline TA: Biochem J Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 313-8 Citation Subset: IM |
Affiliation:
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Laboratory of Neurosciences, National Institutes on Aging, National Institutes of Health, Bethesda, MD, 20892-1582, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acyl Coenzyme A
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metabolism Acylation Adenosine Triphosphate / metabolism Animals Biological Transport Brain / metabolism* Energy Metabolism* Fatty Acids / metabolism Lysophospholipids / metabolism Mammals / metabolism* Membrane Glycoproteins / metabolism Models, Biological* Phospholipids / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Acyl Coenzyme A; 0/Fatty Acids; 0/Lysophospholipids; 0/Membrane Glycoproteins; 0/Phospholipids; 56-65-5/Adenosine Triphosphate |
| Comments/Corrections | |
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