Homogentisic acid

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Homogentisic acid is an organic compound that plays a crucial role in the metabolism of the amino acids tyrosine and phenylalanine. It is a key intermediate in the catabolic pathway of these amino acids.

Biochemistry

Homogentisic acid is formed during the breakdown of tyrosine and phenylalanine through the action of the enzyme homogentisate 1,2-dioxygenase. This enzyme catalyzes the conversion of homogentisic acid to maleylacetoacetic acid, which is further processed in the metabolic pathway.

Medical significance

The accumulation of homogentisic acid in the body is associated with a rare genetic disorder known as alkaptonuria. This condition is caused by a deficiency in the enzyme homogentisate 1,2-dioxygenase, leading to the buildup of homogentisic acid in tissues and its excretion in urine. Over time, this can result in ochronosis, a condition characterized by the darkening of connective tissues, and can lead to arthritis and other complications.

Chemical properties

Homogentisic acid is a dihydroxyphenylacetic acid with the chemical formula C_8H_8O_4. It is a crystalline solid that is soluble in water. The compound has two hydroxyl groups attached to a benzene ring, which makes it a dihydroxy derivative of phenylacetic acid.

Related compounds

Homogentisic acid is structurally related to other phenolic acids, such as gallic acid and protocatechuic acid. It is also related to phenylacetic acid and its derivatives.

See also

• Tyrosine
• Phenylalanine
• Alkaptonuria
• Homogentisate 1,2-dioxygenase
• Ochronosis
• Metabolic pathway