Homogentisic acid

2,5 - dihydroxyphenylacetic

Beige solid


152-154 ° C ( monohydrate)


Template: Infobox chemical / molecular formula search available

Homogentisic acid is an intermediate in the degradation of the amino acids phenylalanine and tyrosine, and is at physiological pH values ​​as an anion at the moment ( homogentisate ). It is used by the enzyme homogentisate dioxygenase ( EC ) is converted into 4- Maleylacetessigsäure:

In consequence, result acetoacetic acid and fumaric acid, which can be fed into the citric acid cycle.

In the metabolic disease alkaptonuria lack the enzyme or is not available to a sufficient extent. " Alkapton " is the oxidized form of the black-brown Homogentisats.