Homogentisate 1,2-dioxygenase

Homogentisate 1,2-dioxygenase (homogentisic acid oxidase, homogentisicase) is an enzyme, which catalyzes the conversion of homogentisate to 4-maleylacetoacetate. Homogentisate 1,2-dioxygenase or HGD is involved in the catabolism of aromatic rings, more specifically in the breakdown of the amino acids tyrosine and phenylalanine. HGD appears in the metabolic pathway of tyrosine and phenylalanine degradation once the molecule homogentisate is produced. Homogentisate reacts with HGD to produce maleylacetoacetate, which then is further used in the metabolic pathway. HGD requires the use of Fe and O₂ in order to cleave the aromatic ring of homogentisate.