Malonyl-CoA
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Names | |
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Preferred IUPAC name
(9R)-1-[(2R,3S,4R,5R)-5-(6-Amino-9H-purin-9-yl)-4-hydroxy-3-(phosphonooxy)oxolan-2-yl]-3,5,9-trihydroxy-3,5,10,14,19-pentaoxo-8,8-dimethyl-2,4,6-trioxa-18-thia-11,15-diaza-3λ5,5λ5-diphosphahenicosan-21-oic acid | |
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ChemSpider | |
ECHA InfoCard | 100.007.596 |
MeSH | Malonyl+CoA |
PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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Properties | |
C24H38N7O19P3S | |
Molar mass | 853.582 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Malonyl-CoA is a coenzyme A derivative of malonic acid.
Biosynthesis
[edit]Malonyl-CoA cannot cross membranes and there is no known malonyl-CoA import mechanism.[1][2] The biosynthesis therefore takes place locally:
- cytosol: Malonyl-CoA is formed by carboxylating acetyl-CoA using the highly regulated enzyme acetyl-CoA carboxylase 1 (ACC1). One molecule of acetyl-CoA joins with a molecule of bicarbonate,[3] requiring energy rendered from ATP.
- mitochondrial outer membran: Malonyl-CoA is formed by carboxylating acetyl-CoA using the highly regulated enzyme acetyl-CoA carboxylase 2 (ACC2). The reaction is the same as with ACC1.
- mitochondrial matrix: Malonyl-CoA is formed in coordinated fashion by mtACC1, a mitochondrial isoform of ACC1, and acyl-CoA synthetase family member 3 (ACSF3), a mitochondrial malonyl-CoA synthetase.[4] MtACC1, like cytosolic ACC1 catalyses the carboxylation of acetyl-CoA, while ACSF3 catalyses the thioesterification of malonate to coenzyme A.[5][4] The latter serves for the clearance of mitochondrial malonate, since malonate is a potent inhibitor of mitochondrial respiration as it competitively inhibits succinate dehydrogenase.[6] However, the source of malonyl-CoA in the mitochondria is still up for debate.[2]
Functions
[edit]It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis.
Cytosolic malonyl-CoA
[edit]Malonyl-CoA provides 2-carbon units to fatty acids and commits them to fatty acid chain synthesis.
Malonyl-CoA is utilised in fatty acid biosynthesis by the enzyme malonyl coenzyme A:acyl carrier protein transacylase (MCAT). MCAT serves to transfer malonate from malonyl-CoA to the terminal thiol of holo-acyl carrier protein (ACP).
Malonyl-CoA is a highly regulated molecule in fatty acid synthesis; as such, it inhibits the rate-limiting step in beta-oxidation of fatty acids.[6] Malonyl-CoA inhibits fatty acids from associating with carnitine by regulating the enzyme carnitine palmitoyltransferase, thereby preventing them from entering the mitochondria, where fatty acid oxidation and degradation occur.
Polyketide biosynthesis
[edit]MCAT is also involved in bacterial polyketide biosynthesis. The enzyme MCAT together with an acyl carrier protein (ACP), and a polyketide synthase (PKS) and chain-length factor heterodimer, constitutes the minimal PKS of type II polyketides.
Clinical relevance
[edit]Malonyl-CoA plays a special role in the mitochondrial clearance of toxic malonic acid in the metabolic disorders combined malonic and methylmalonic aciduria (CMAMMA) and malonic aciduria.[6] In CMAMMA, malonyl-CoA synthetase, ACSF3 is impaired, which generates mitochondrial malonyl-CoA from malonic acid, which can then be converted to acetyl-CoA by malonyl-CoA decarboxylase.[5][6] In contrast, in malonic aciduria, malonyl-CoA decarboxylase is decreased, which converts malonyl-CoA to acetyl-CoA.[6]
See also
[edit]References
[edit]- ^ Bowman, Caitlyn E.; Rodriguez, Susana; Selen Alpergin, Ebru S.; Acoba, Michelle G.; Zhao, Liang; Hartung, Thomas; Claypool, Steven M.; Watkins, Paul A.; Wolfgang, Michael J. (2017). "The Mammalian Malonyl-CoA Synthetase ACSF3 Is Required for Mitochondrial Protein Malonylation and Metabolic Efficiency". Cell Chemical Biology. 24 (6): 673–684.e4. doi:10.1016/j.chembiol.2017.04.009. PMC 5482780. PMID 28479296.
- ^ a b Nowinski, Sara M.; Van Vranken, Jonathan G.; Dove, Katja K.; Rutter, Jared (October 2018). "Impact of Mitochondrial Fatty Acid Synthesis on Mitochondrial Biogenesis". Current Biology. 28 (20): R1212 – R1219. Bibcode:2018CBio...28R1212N. doi:10.1016/j.cub.2018.08.022. PMC 6258005. PMID 30352195.
- ^ Nelson D, Cox M (2008). Lehninger principles of biochemistry (5th ed.). p. 806.
- ^ a b Monteuuis, Geoffray; Suomi, Fumi; Kerätär, Juha M.; Masud, Ali J.; Kastaniotis, Alexander J. (2017-11-15). "A conserved mammalian mitochondrial isoform of acetyl-CoA carboxylase ACC1 provides the malonyl-CoA essential for mitochondrial biogenesis in tandem with ACSF3". Biochemical Journal. 474 (22): 3783–3797. doi:10.1042/BCJ20170416. ISSN 0264-6021. PMID 28986507.
- ^ a b Witkowski, Andrzej; Thweatt, Jennifer; Smith, Stuart (September 2011). "Mammalian ACSF3 Protein Is a Malonyl-CoA Synthetase That Supplies the Chain Extender Units for Mitochondrial Fatty Acid Synthesis". Journal of Biological Chemistry. 286 (39): 33729–33736. doi:10.1074/jbc.M111.291591. ISSN 0021-9258. PMC 3190830. PMID 21846720.
- ^ a b c d e Bowman, Caitlyn E.; Wolfgang, Michael J. (January 2019). "Role of the malonyl-CoA synthetase ACSF3 in mitochondrial metabolism". Advances in Biological Regulation. 71: 34–40. doi:10.1016/j.jbior.2018.09.002. PMC 6347522. PMID 30201289.