Oxalsuccinic acid
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| General | |||||||||||||||||||
| Surname | Oxalsuccinic acid | ||||||||||||||||||
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| Molecular formula | C 6 H 6 O 7 | ||||||||||||||||||
| Brief description |
colorless crystals |
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| properties | |||||||||||||||||||
| Molar mass | 190.1 g mol −1 | ||||||||||||||||||
| Melting point |
80.5 ° C (decomposition) > |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||||||||
Oxalsuccinic acid is the common name of an organic tricarboxylic acid or a β-ketocarboxylic acid. It was discovered in 1948 by the biochemists Severo Ochoa and Feodor Lynen . The free acid is unstable and breaks down into a keto compound, while its salts , the oxalosuccinates (also known as oxalosuccinates) , are stable .
properties
Oxalsuccinic acid forms colorless, prism-shaped crystals that melt at 80.5 ° C. In the melt, decomposition takes place with the release of carbon dioxide with the formation of α-ketoglutaric acid as a reaction product. A keto-enol balance can be formulated for connection. While only the keto form is present in the solid, up to 25% of the substance can be present in the enol form in solutions in organic solvents such as ethyl acetate or diethyl ether .
Occurrence
Oxalsuccinic acid (or its salts) is an intermediate product in the carbohydrate metabolism of oxygen-consuming organisms. In this metabolic sequence, the citric acid cycle , it is created by oxidation from isocitric acid . It is converted into α-ketoglutaric acid by decarboxylation . Both steps take place without the substrate separating from the enzyme , isocitrate dehydrogenase . This (and with it the formation of oxalosuccinic acid) was postulated by Carl Martins as early as 1937 .
Individual evidence
- ↑ a b c d Feodor Lynen, Helmut Scherer: The representation of oxalucinic acid and the fermentation system of its decarboxylation - on the biological degradation of acetic acid V. In: Justus Liebigs Annalen der Chemie. 560, 1948, pp. 163-190, doi : 10.1002 / jlac.19485600202 .
- ↑ There is not yet a harmonized classification for this substance . A label of [No public or meaningful name is available] in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on July 26, 2017, is derived from a self-classification by the distributor .
- ↑ Hans Krebs: Lecture on the award of the Nobel Prize, December 11, 1953, p. 404. ( Memento of November 6, 2014 in the Internet Archive )
- ↑ S. Ochoa: Biosynthesis of tricarboxylic acids by carbon dioxide fixation; the preparation and properties of oxalosuccinic acid. In: Journal of Biological Chemistry . Volume 174, Number 1, May 1948, pp. 115-122, PMID 18914069 .
- ↑ Feodor Lynen, Hans Bayer, Helmut Holzer: On the desmotropy of oxalsuccinic acid in Justus Liebig's Annalen der Chemie 562 (1949) 66–73, doi : 10.1002 / jlac.19495620108 .
- ↑ Carl Martins: About the breakdown of citric acid. In: Hoppe-Seyler's magazine for physiological chemistry. 247, 1937, p. 104, doi : 10.1515 / bchm2.1937.247.3.104 .