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Record Information
Version1.0
StatusDetected and Quantified
Creation Date2021-11-23 23:06:06 UTC
Update Date2024-10-13 14:48:44 UTC
Metabolite IDMMDBc0047902
Metabolite Identification
Common NameHomogentisic acid
DescriptionHomogentisic acid, also known as melanic acid, is an intermediate in the breakdown or catabolism of tyrosine and phenylalanine. It is generated from the compound p-hydroxyphenylpyruvate through the enzyme p-hydroxyphenylpyruvate dehydrogenase. The resulting homogentisic acid is then broken down into 4-maleylacetoacetate via the enzyme homogentisate 1,2-dioxygenase. Homogentisic acid is also found in other organisms. For instance, it can found in Arbutus unedo (strawberry-tree) honey, in the bacterial plant pathogen Xanthomonas campestris as well as in the yeast Yarrowia lipolytica where it is associated with the production of brown pigments. Homogentisic acid can be oxidatively dimerized to form hipposudoric acid, one of the main constituents of the 'blood sweat' of hippopotamuses. When present in sufficiently high levels, homogentisic acid can function as an osteotoxin and a renal toxin. An osteotoxin is a substance that causes damage to bones and/or joints. A renal toxin causes damage to the kidneys. Chronically high levels of homogentisic acid are associated with alkaptonuria (OMIM: 203500 ), an inborn error of metabolism. Alkaptonuria is a rare inherited genetic disorder in which the body cannot process the amino acids phenylalanine and tyrosine. It is caused by a mutation in the enzyme homogentisate 1,2-dioxygenase (EC 1.13.11.5), which leads to an accumulation of homogentisic acid in the blood and tissues. Homogentisic acid and its oxidized form benzoquinone acetic acid are excreted in the urine, giving it an unusually dark color. The accumulating homogentisic acid (and benzoquinone acetic acid) causes damage to cartilage (ochronosis, leading to osteoarthritis) and heart valves as well as precipitating as kidney stones and stones in other organs. More specifically, homogentisic acid can be converted to benzoquinone acetic acid (BQA), and the resulting BQA can be readily converted to polymers that resemble the dark skin pigment melanin. These polymers are deposited in the collagen, a connective tissue protein, of particular tissues such as cartilage. This process is called ochronosis (as the tissue looks ochre); ochronotic tissue is stiffened and unusually brittle, impairing its normal function and causing damage. Homogentisic acid is the primary precursor of melanin synthesis in Vibrio cholerae.
Structure
Synonyms
ValueSource
2,5-Dihydroxyphenylacetic acidChEBI
2-(3,6-DIHYDROXYPHENYL)acetIC ACIDChEBI
2,5-DihydroxyphenylacetateKegg
2-(3,6-DIHYDROXYPHENYL)acetateGenerator
HomogentisateGenerator
(2,5-Dihydroxyphenyl)-acetateHMDB
(2,5-Dihydroxyphenyl)-acetic acidHMDB
2,5-Dihydroxy-a-toluateHMDB
2,5-Dihydroxy-a-toluic acidHMDB
2,5-Dihydroxy-alpha-toluateHMDB
2,5-Dihydroxy-alpha-toluic acidHMDB
2,5-Dihydroxy-benzeneacetateHMDB
2,5-Dihydroxy-benzeneacetic acidHMDB
AlcaptonHMDB
Homogentisate acidHMDB
HomogentisinateHMDB
Homogentisinic acidHMDB
Melanic acidHMDB
Acid, homogentisicHMDB
Molecular FormulaC8H8O4
Average Mass168.1467
Monoisotopic Mass168.042258744
IUPAC Name2-(2,5-dihydroxyphenyl)acetic acid
Traditional Namehomogentisic acid
CAS Registry Number451-13-8
SMILES
OC(=O)CC1=C(O)C=CC(O)=C1
InChI Identifier
InChI=1S/C8H8O4/c9-6-1-2-7(10)5(3-6)4-8(11)12/h1-3,9-10H,4H2,(H,11,12)
InChI KeyIGMNYECMUMZDDF-UHFFFAOYSA-N