Homogentisic acid
Structural formula | ||||||||||||||||||||||
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General | ||||||||||||||||||||||
Surname | Homogentisic acid | |||||||||||||||||||||
other names |
2,5-dihydroxyphenylacetic acid |
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Molecular formula | C 8 H 8 O 4 | |||||||||||||||||||||
Brief description |
beige solid |
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properties | ||||||||||||||||||||||
Molar mass | 168.15 g mol −1 | |||||||||||||||||||||
Physical state |
firmly |
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Melting point |
152–154 ° C (monohydrate) |
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safety instructions | ||||||||||||||||||||||
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Homogentisic acid is an intermediate product of the breakdown of the amino acids phenylalanine and tyrosine and is present as an anion ( homogenate ) at physiological pH values . It is converted into 4-maleyl acetic acid by the enzyme homogenate dioxygenase ( EC 1.13.11.5 ):
As a result, acetoacetic acid and fumaric acid are formed , which can be fed into the citric acid cycle .
In alkaptonuria , a metabolic disease , the enzyme is absent or not present in sufficient quantities. "Alkapton" is the oxidized, black-brown form of the homogenate.
See also
Individual evidence
- ↑ a b c data sheet Homogentisic acid from Sigma-Aldrich , accessed on April 4, 2011 ( PDF ).
- ↑ a b entry on homogentisic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 16, 2014.