| 3-Hydroxy-3-methylglutaryl coenzyme A reductase: regulation of enzymatic activity by phosphorylation and dephosphorylation. | |
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MedLine Citation:
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PMID: 278983 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The activity of microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) [mevalonate:NADP+ oxidoreductase (CoA-acylating); EC 1.1.1.34] was inhibited by ATP+Mg2+. Inactivation of HMG-CoA reductase by ATP+Mg2+ was dependent on time, temperature, and ATP concentration. Incubation of microsomal HMG-CoA reductase with [gamma-32P]ATP+Mg2+ was associated with a reciprocal increase in [32P]protein-bound radioactivity and a decrease in enzymatic activity. Incubation of 32P-labeled microsomal HMG-CoA reductase with a partially purified cytosolic phosphatase resulted in a time-dependent reciprocal release of [32P]protein-bound radioactivity and reactivation of enzyme activity. Phosphorylation of HMG-CoA reductase was confirmed by immunoprecipitation of partially purified [gamma-32P]-ATP+Mg2+-inactivated microsomal HMG-CoA reductase with a reductase-specific antiserum. Sodium dodecyl sulfate electrophoresis of the [gamma-32P]immunoprecipitate revealed that the 32P radioactivity was located in the electrophoretic position of HMG-CoA reductase. These results established that the reversible inactivation of HMG-CoA reductase by ATP+Mg2+ was due to covalent modification of the enzyme by a phosphorylation-dephosphorylation reaction sequence. The existence of HMG-CoA reductase in interconvertible active and inactive forms provides a mechanism for the rapid short-term regulation of the pathway for cholesterol biosynthesis. |
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Authors:
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Z H Beg; J A Stonik; H B Brewer |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Proceedings of the National Academy of Sciences of the United States of America Volume: 75 ISSN: 0027-8424 ISO Abbreviation: Proc. Natl. Acad. Sci. U.S.A. Publication Date: 1978 Aug |
Date Detail:
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Created Date: 1978-12-02 Completed Date: 1978-12-02 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 7505876 Medline TA: Proc Natl Acad Sci U S A Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 3678-82 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Triphosphate Enzyme Activation Hydroxymethylglutaryl CoA Reductases / metabolism* Magnesium Microsomes / enzymology Phosphorylation Temperature Time Factors |
| Chemical | |
Reg. No./Substance:
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56-65-5/Adenosine Triphosphate; 7439-95-4/Magnesium; EC 1.1.1.-/Hydroxymethylglutaryl CoA Reductases |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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