4-hydroxyphenylpyruvate

4-Hydroxyphenylpyruvate (4-HPP) is an intermediate in the metabolism of the amino acid phenylalanine. It is converted from phenylpyruvate by the enzyme phenylpyruvate tautomerase and is further metabolized to homogentisate by the enzyme 4-hydroxyphenylpyruvate dioxygenase.

Metabolism

4-Hydroxyphenylpyruvate is involved in the phenylalanine metabolism pathway. It is produced from phenylpyruvate by the enzyme phenylpyruvate tautomerase. This reaction is a part of the larger phenylalanine degradation pathway, which is responsible for breaking down phenylalanine into smaller molecules that can be used by the body.

The next step in the pathway involves the conversion of 4-hydroxyphenylpyruvate to homogentisate by the enzyme 4-hydroxyphenylpyruvate dioxygenase. Homogentisate is then further metabolized into fumarate and acetoacetate, which can enter the citric acid cycle.

Clinical significance

Deficiency in the enzyme 4-hydroxyphenylpyruvate dioxygenase can lead to a rare metabolic disorder known as Hawkinsinuria. This condition is characterized by the excretion of hawkinsin, a metabolite of 4-hydroxyphenylpyruvate, in the urine.

Alkaptonuria is another metabolic disorder that can result from a deficiency in the enzyme homogentisate 1,2-dioxygenase, which is responsible for the conversion of homogentisate to fumarate and acetoacetate. This condition is characterized by the accumulation of homogentisate in the body, leading to a variety of symptoms including darkening of the urine and blue-black discoloration of the skin and connective tissues.

See also

• Phenylalanine
• Phenylpyruvate
• Homogentisate
• Hawkinsinuria
• Alkaptonuria

4-hydroxyphenylpyruvate Resources
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