<p>Fumarylacetoacetase (<db_xref db="EC" dbkey="3.7.1.2"/>; also known as fumarylacetoacetate hydrolase or FAH) catalyses the hydrolytic cleavage of a carbon-carbon bond in fumarylacetoacetate to yield fumarate and acetoacetate as the final step in phenylalanine and tyrosine degradation [<cite idref="PUB00025833"/>]. This is an essential metabolic function in humans, the lack of FAH causing type I tyrosinaemia, which is associated with liver and kidney abnormalities and neurological disorders [<cite idref="PUB00002007"/>, <cite idref="PUB00035625"/>]. The enzyme mechanism involves a catalytic metal ion, a Glu/His catalytic dyad, and a charged oxyanion hole [<cite idref="PUB00022554"/>]. FAH folds into two domains: an N-terminal domain SH3-like beta-barrel, and a C-terminal with an unusual fold consisting of three layers of beta-sheet structures [<cite idref="PUB00022554"/>].</p><p>This entry represents the C-terminal domain of fumarylacetoacetase, as well as other domains that share a homologous alpha/beta structure, including:</p><ul><li>5-carboxymethyl-2-hydroxymuconate delta-isomerase (CHM isomerase; <db_xref db="EC" dbkey="5.3.3.10"/>), which catalyses the conversion of 5-carboxymethyl-2-hydroxymuconate to 5-carboxy-2-oxohept-3-enedioate [<cite idref="PUB00035626"/>].</li><li>5-oxopent-3-ene-1,2,5-tricarboxylate decarboxylase (OPET decarboxylase; <db_xref db="EC" dbkey="4.1.1.68"/>), which catalyses the conversion of 5-oxopent-3-ene-1,2,5-tricarboxylate to 2-oxohept-3-enedioate and carbon dioxide.</li><li>Bifunctional enzyme HpcE (OPET decarboxylase <db_xref db="EC" dbkey="4.1.1.68"/>/HHDD isomerase <db_xref db="EC" dbkey="5.3.3.10"/>), which is a duplication consisting of a tandem repeat of two FAH C-terminal-like domains. This enzyme is responsible for the degradation of 4-hydroxyphenylacetate, a product of tyrosine and phenylalanine metabolism also released by lignin catabolism [<cite idref="PUB00016709"/>]. </li><li>2-keto-4-pentenoate hydratase MhpD (<db_xref db="EC" dbkey="4.2.1.80"/>; also known as 2-oxopent-4-enoate hydratase), which converts 4-hydroxy-2-oxopentanoate to 2-oxopent-4-enoate [<cite idref="PUB00035627"/>].</li><li>4-oxalocrotonate decarboxylase (4-OD; <db_xref db="EC" dbkey="4.1.1.77"/>), which catalyses the conversion of 4-oxalocrotonate to 2-oxopent-4-enoate and carbon dioxide [<cite idref="PUB00035628"/>].</li><li>2-oxo-hepta-3-ene-1,7-dioic acid hydratase, which hydrates the double bond of 2-oxo-hepta-3-ene-1,7-dioic acid to form 4-hydroxy-2-oxo-heptane-1,7-dioic acid in the catabolism of 4-hydroxyphenylacetic acid.</li></ul> Fumarylacetoacetase, C-terminal-related