Homogentisic acid
Chemical compound
From Wikipedia, the free encyclopedia
Homogentisic acid (2,5-dihydroxyphenylacetic acid) is a phenolic acid usually found in Arbutus unedo (strawberry-tree) honey.[1] It is also present in the bacterial plant pathogen Xanthomonas campestris pv. phaseoli[2] as well as in the yeast Yarrowia lipolytica[3] where it is associated with the production of brown pigments. It is oxidatively dimerised to form hipposudoric acid, one of the main constituents of the 'blood sweat' of hippopotamuses.
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| Names | |
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| Preferred IUPAC name
(2,5-Dihydroxyphenyl)acetic acid | |
| Other names
Melanic acid | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
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| DrugBank | |
| ECHA InfoCard | 100.006.540 |
| KEGG | |
| MeSH | Homogentisic+acid |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C8H8O4 | |
| Molar mass | 168.148 g·mol−1 |
| Melting point | 150 to 152 °C (302 to 306 °F; 423 to 425 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It is less commonly known as melanic acid, the name chosen by William Prout.
Human pathology
Accumulation of excess homogentisic acid and its oxide, named alkapton, is a result of the failure of the enzyme homogentisic acid 1,2-dioxygenase (typically due to a mutation) in the degradative pathway of tyrosine, consequently associated with alkaptonuria.[4]
Intermediate
It is an intermediate in the catabolism of aromatic amino acids such as phenylalanine and tyrosine.
4-Hydroxyphenylpyruvate (produced by transamination of tyrosine) is acted upon by the enzyme 4-hydroxyphenylpyruvate dioxygenase to yield homogentisate.[5] If active and present, the enzyme homogentisate 1,2-dioxygenase further degrades homogentisic acid to yield 4-maleylacetoacetic acid.[6]