4-Maleylacetoacetic acid

Chemical compound

4-Maleylacetoacetic acid is an intermediate in the catabolic pathway of the amino acid tyrosine. It is a dicarboxylic acid and plays a crucial role in the metabolism of aromatic amino acids.

Structure and Properties

4-Maleylacetoacetic acid is characterized by its chemical structure, which includes a maleyl group attached to an acetoacetic acid moiety. The presence of conjugated double bonds in the maleyl group is a distinctive feature of this compound.

Chemical structure of 4-Maleylacetoacetic acid

Biological Role

In the tyrosine metabolism pathway, 4-maleylacetoacetic acid is formed from the oxidation of homogentisic acid by the enzyme homogentisate 1,2-dioxygenase. This reaction is a critical step in the breakdown of tyrosine, leading to the production of fumarate and acetoacetate, which are further utilized in the citric acid cycle and ketogenesis, respectively.

Enzymatic Conversion

The conversion of 4-maleylacetoacetic acid to fumarylacetoacetic acid is catalyzed by the enzyme maleylacetoacetate isomerase. This enzyme facilitates the isomerization of the maleyl group to a fumaryl group, which is a necessary step for the continuation of the tyrosine degradation pathway.

Clinical Significance

Deficiencies in the enzymes involved in the metabolism of 4-maleylacetoacetic acid can lead to metabolic disorders. For example, a deficiency in fumarylacetoacetate hydrolase, the enzyme that acts downstream of maleylacetoacetate isomerase, results in the accumulation of toxic intermediates and is associated with the condition known as tyrosinemia type I.

Related pages

• Tyrosine metabolism
• Homogentisic acid
• Fumarylacetoacetate hydrolase
• Tyrosinemia

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  4-Maleylacetoacetic acid