tyrosine catabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of tyrosine, an aromatic amino acid, 2-amino-3-(4-hydroxyphenyl)propanoic acid. [GOC:go_curators]

Tyrosine catabolism is the breakdown of the amino acid tyrosine, a process essential for energy production and the synthesis of various biomolecules. The breakdown of tyrosine begins with its conversion to p-hydroxyphenylpyruvate (HPP) through the enzyme tyrosine aminotransferase. HPP is then decarboxylated by the enzyme 4-hydroxyphenylpyruvate decarboxylase to form homogentisate. Homogentisate is then oxidized to maleylacetoacetate by the enzyme homogentisate 1,2-dioxygenase. Maleylacetoacetate is then isomerized to fumarylacetoacetate by the enzyme maleylacetoacetate isomerase. Finally, fumarylacetoacetate is cleaved by the enzyme fumarylacetoacetate hydrolase to form fumarate and acetoacetate. These two products are intermediates in the citric acid cycle and can be used for energy production. Tyrosine catabolism is also important for the synthesis of melanin, a pigment that gives skin, hair, and eyes their color. Tyrosine is converted to melanin through a series of enzymatic reactions involving the enzyme tyrosinase. Tyrosine catabolism is tightly regulated and is influenced by factors such as dietary intake of tyrosine, hormonal signals, and the activity of specific enzymes. Defects in tyrosine catabolism can lead to a number of genetic diseases, including alkaptonuria, tyrosinemia, and hereditary tyrosinemia type I. Alkaptonuria is characterized by the accumulation of homogentisate, which leads to the deposition of a black pigment in the urine, cartilage, and connective tissues. Tyrosinemia is characterized by the accumulation of tyrosine and its metabolites, which can lead to liver failure, kidney failure, and neurological problems. Hereditary tyrosinemia type I is the most severe form of tyrosinemia and can lead to death in early childhood. These diseases highlight the importance of tyrosine catabolism for normal human health.'
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Proteins (3)

Compounds (8)