Methylmalonic acid
| Methylmalonic acid | |
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methylmalonic acid |
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Other names
2-methylpropanedioic acid |
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| Identifiers | |
| CAS number | 516-05-2 |
| PubChem | 487 |
| MeSH | Methylmalonic+acid |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C4H6O4 |
| Molar mass | 118.09 g mol−1 |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Methylmalonic acid (MMA) 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.
[edit] Pathology
Increased methylmalonic acid levels may indicate a vitamin B12 deficiency. However, it is sensitive without being specific. MMA is elevated in 90-98% of patients with B12 deficiency. This test may be overly sensitive, 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. [1]
An excess is associated with methylmalonic acidemia.
MMA concentrations in blood are measured by Gas chromatographic Mass spectrometry and the expected values of MMA in healthy people are between 73-271 nmol/L. [2]
