Methylmalonic acid
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Names | |
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IUPAC name
2-Methylpropanedioic acid | |
Other names
Methylmalonic acid | |
Identifiers | |
3D model (JSmol) |
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ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.007.473 |
EC Number | 208-219-5 |
KEGG | |
MeSH | Methylmalonic+acid |
PubChem CID |
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Properties | |
C4H6O4 | |
Molar mass | 118.088 g/mol |
Density | 1.455 g/cm−3 |
Melting point | 134 °C (273 °F; 407 K) |
Acidity (pKa) | pKa1 = 3,07[1] pKa2 = 5,76[1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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Infobox references | |
Methylmalonic acid (MMA) (conjugate base methylmalonate) is a dicarboxylic acid that is a C-methylated derivative of malonate.
The coenzyme A linked form of methylmalonic acid, methylmalonyl-CoA, is converted into succinyl-CoA by methylmalonyl-CoA mutase, in a reaction that requires vitamin B12 as a cofactor. In this way, it enters the Krebs cycle, and is thus part of one of the anaplerotic reactions.
Pathology
Increased methylmalonic acid levels may indicate a vitamin B12 deficiency. However, it is sensitive (those with the disease almost always test positive) but not specific (those that do not have the disease do not always test negative).[2] MMA is elevated in 90–98% of patients with B12 deficiency. It has lower specificity as 20–25% of patients over the age of 70 have elevated levels of MMA, but 25–33% of them do not have B12 deficiency. For this reason, MMA test is not routinely recommended in the elderly.[3]
An excess is associated with methylmalonic acidemia.
MMA concentrations in blood are measured by gas chromatographic mass spectrometry or LC-MS and the expected values of MMA in healthy people are between 73–271 nmol/L.[4][5]
See also
References
- 1 2 "Dissociation Constants Of Organic Acids And Bases". zirchrom.com.
- ↑ "Sensitivity and Specificity". www.med.emory.edu.
- ↑ "B12 Deficiiency and Dizziness". www.dizziness-and-balance.com.
- ↑ http://scidok.sulb.uni-saarland.de/volltexte/2007/1076/pdf/Thesis.pdf
- ↑ "Methylmalonic Acid, Serum or Plasma (Vitamin B12 Status)". ltd.aruplab.com.