3D rendering of Homogentisate Dioxygenase with active site amino acid residues and Iron atom colored. Histidine is the tan color, Glutamate the red color, and Iron is the blue.
Homogentisate 1,2-dioxygenase (homogentisic acid oxidase, homogentisate 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.[1] 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 Fe2+ and O2 in order to cleave the aromatic ring of homogentisate.[2]
^Titus GP, Mueller HA, Burgner J, Rodríguez De Córdoba S, Peñalva MA, Timm DE (Jul 2000). "Crystal structure of human homogentisate dioxygenase". Nature Structural Biology. 7 (7): 542–6. doi:10.1038/76756. hdl:10261/71724. PMID10876237. S2CID6219553.
^Borowski T, Georgiev V, Siegbahn PE (Dec 2005). "Catalytic reaction mechanism of homogentisate dioxygenase: a hybrid DFT study". Journal of the American Chemical Society. 127 (49): 17303–14. doi:10.1021/ja054433j. PMID16332080.
