| Lipid metabolism in human platelets. I. Evidence for a complete fatty acid synthesizing system. | |
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MedLine Citation:
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PMID: 5765018 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Extracts from human platelets contain the enzymes of de novo fatty acid biosynthesis. The pattern of incorporation of acetate-1-(14)C into fatty acids by intact platelets indicates that these enzymes function in platelets. The level of acetyl-coenzyme A (CoA) carboxylase activity in extracts of platelets from normal subjects is 0.036 +/-0.01 mmumole of malonyl-CoA formed per min per mg of protein and that of fatty acid synthetase is 0.075 +/-0.016 mmumole of malonyl-CoA utilized per min per mg of protein. Thus, platelets are the only formed elements of the blood capable of de novo fatty acid synthesis. The capacity of platelets to synthesize fatty acids is similar to human liver based on enzyme activity per milligram of soluble protein.Acetyl-CoA carboxylase was purified 16-fold from platelet extracts, and this partially purified enzyme was compared to enzyme from rat liver. The two enzymes were similar with respect to requirements, substrate affinities, pH profile of activity, inhibition by malonyl-CoA, and aggregation in the presence of citrate. Thus, while fatty acid synthesis may serve a different function in platelets than in liver, the properties of acetyl-CoA carboxylase from these tissues are alike. The levels of the enzymes of fatty acid synthesis were significantly higher in platelets from splenectomized subjects than in controls. Acetyl-CoA carboxylase levels were 0.086 +/-0.027 mmumole of malonyl-CoA formed per min per mg of protein, and fatty acid synthetase levels were 0.151 +/-0.039 mmumole of malonyl-CoA utilized per min per mg of protein. These changes in the enzymes of fatty acid synthesis occurred promptly after splenectomy with peak values being reached within 7-10 days. |
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Authors:
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P W Majerus; M B Smith; G H Clamon |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Journal of clinical investigation Volume: 48 ISSN: 0021-9738 ISO Abbreviation: J. Clin. Invest. Publication Date: 1969 Jan |
Date Detail:
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Created Date: 1969-04-01 Completed Date: 1969-04-01 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 7802877 Medline TA: J Clin Invest Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 156-64 Citation Subset: AIM; IM |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Blood Platelets
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enzymology,
metabolism* Carbon Isotopes Centrifugation, Density Gradient Chromatography, Gas Fatty Acids / biosynthesis* Glucosephosphate Dehydrogenase / blood Humans Ligases / blood* Liver / enzymology Spleen / physiology Splenectomy |
| Chemical | |
Reg. No./Substance:
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0/Carbon Isotopes; 0/Fatty Acids; EC 1.1.1.49/Glucosephosphate Dehydrogenase; EC 6.-/Ligases |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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