[{"from": "human", "value": "Please give me some details about this molecule. [C][=C][C][=Branch1][#C][=C][Branch1][=Branch1][C][=C][Ring1][=Branch1][O][C][C][=Branch1][C][=O][O][O]"}, {"from": "gpt", "value": "The molecule is an intermediate of the metabolic breakdown of tyrosine and phenylalanine; it occurs in the urine in cases of alkaptonuria. (OMIN 203500) Homogentisic acid is the primary precursor of melanin synthesis in Vibrio cholerae."}]