Homogentisic acid


Homogentisic acid is a phenolic acid usually found in Arbutus unedo honey. It is also present in the bacterial plant pathogen Xanthomonas campestris pv. phaseoli as well as in the yeast Yarrowia lipolytica 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.
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 in the degradative pathway of tyrosine, consequently associated with alkaptonuria.

Intermediate

It is an intermediate in the catabolism of aromatic amino acids such as phenylalanine and tyrosine.