Homogentisate 1,2-Dioxygenase

**Definition:** A mononuclear Fe(II)-dependent oxygenase, this enzyme catalyzes the conversion of homogentisate to 4-maleylacetoacetate, the third step in the pathway for the catabolism of TYROSINE. Deficiency in the enzyme causes ALKAPTONURIA, an autosomal recessive disorder, characterized by homogentisic aciduria, OCHRONOSIS and ARTHRITIS. This enzyme was formerly characterized as EC 1.13.1.5 and EC 1.99.2.5.

**Tree numbers:** - D08.811.682.690.416.326

**Synonyms:** - Homogentisate Dioxygenase - Homogentisate Oxidase - Homogentisate Oxygenase - Homogentisic Acid Oxidase