2-Methylmaleate
Citraconic acid, also known as 2-methylmaleate or methylmaleic acid, belongs to the class of organic compounds known as methyl-branched fatty acids. These are fatty acids with an acyl chain that has a methyl branch. Usually, they are saturated and contain only one or more methyl group. However, branches other than methyl may be present. Citraconic acid is a dicarboxylic acid consisting of maleic acid having a methyl substituent at the 2-position. Citraconic acid exists as a white solid. It is the cis-isomer of mesaconic acid and is one of the pyrocitric acids formed upon the heating of citric acid. Citraconic acid has been detected in the urine of both normal and fasting individuals (PMID: 6778884). Citraconic acid is also elevated in the urine of individuals with methylmalonic acidaemia who have suffered ketotic attacks (PMID: 116077). Altered serum levels of citraconic acid have been detected in patients with primary biliary cholangitis (PMID: 28400566).
| ID | EC Number | Name |
|---|---|---|
| KEGG:R03896 | 4.2.1.35 | (R)-2-methylmalate hydro-lyase (2-methylmaleate-forming) |
| KEGG:R03897 | C02226 + C00001<=>C06031 | |
| KEGG:R03898 | 4.2.1.35 | 2-methylmaleate hydratase; |
| BioCyc:R-2-METHYLMALATE-DEHYDRATASE-RXN | 4.2.1.35 | CPD-31<=>2-METHYLMALEATE + WATER |
| BioCyc:RXN-16946 | 3.7.1.23 | CPD-18271 + WATER --> 2-METHYLMALEATE + PYRUVATE + PROTON |
| BioCyc:RXN-7744 | 2-METHYLMALEATE + WATER --> CPD-7066 | |
| BioCyc:RXN-16948 | 3.7.1.23 | CPD-18273 + WATER --> 2-METHYLMALEATE + PYRUVATE + PROTON |