What is the function of phenylalanine hydroxylase enzyme?

What is the function of phenylalanine hydroxylase enzyme?

Phenylalanine hydroxylase is responsible for the conversion of phenylalanine to another amino acid, tyrosine. The enzyme works with a molecule called tetrahydrobiopterin (BH4) to carry out this chemical reaction.

What type of enzyme is phenylalanine hydroxylase?

PAH is one of three members of the biopterin-dependent aromatic amino acid hydroxylases, a class of monooxygenase that uses tetrahydrobiopterin (BH4, a pteridine cofactor) and a non-heme iron for catalysis.

What happens when phenylalanine is converted to tyrosine?

Phenylalanine and Tyrosine Phenylalanine is metabolized into acetoacetic acid and fumaric acid via tyrosine. A tyrosine metabolite, DOPA, is converted into the neurotransmitters epinephrine and norepinephrine. A lack of these neurotransmitters is a causal factor in Parkinson disease and schizophrenia.

What is the expected result of a deficiency in the enzyme phenylalanine hydroxylase in children with phenylketonuria PKU )?

Signs and symptoms include nearly invariable severe intellectual disability and behavior problems with a high frequency of seizures and variable microcephaly. The excretion of excessive phenylalanine and its metabolites can create a musty body odor and skin conditions such as eczema.

What enzyme converts phenylalanine to tyrosine?

2 encoding the L-phenylalanine hydroxylase enzyme (EC 1.14. 16.1). The PAH enzyme converts phenylalanine to tyrosine in the presence of molecular oxygen and catalytic amounts of tetrahydrobiopterin (BH4), its nonprotein cofactor.

What is the function of tyrosine?

Tyrosine is a nonessential amino acid the body makes from another amino acid called phenylalanine. It is an essential component for the production of several important brain chemicals called neurotransmitters, including epinephrine, norepinephrine, and dopamine.

What produces phenylalanine hydroxylase?

Liver cells contain an enzyme called phenylalanine hydroxylase, which can add this group and convert phenylalanine to tyrosine. Thus as long as this enzyme is functional and there is a reasonable supply of phenylalanine, tyrosine can be synthesized in your body and does not have to be included in the food that you eat.

Is phenylalanine hydroxylase liver enzyme?

PATHOGENESIS AND PATHOPHYSIOLOGY. Although phenylalanine hydroxylase (PAH) is a liver enzyme, the clinical manifestations of classic PKU relate to the CNS.

What is phenylalanine hydroxylase deficiency?

Abstract. Phenylalanine hydroxylase deficiency is an autosomal recessive disorder that results in intolerance to the dietary intake of the essential amino acid phenylalanine. It occurs in approximately 1:15,000 individuals.

What does tyrosine make?

What is a deficiency of the enzyme phenylalanine hydroxylase?

Phenylalanine hydroxylase deficiency (PAH deficiency), also called phenylketonuria (PKU), is an inherited disease in which the body cannot properly process the amino acid phenylalanine due to a deficient enzyme called phenylalanine hydroxylase.

What is the chemical reaction catalyzed by phenylalanine hydroxylase?

Phenylalanine hydroxylase (PheH) catalyzes the hydroxylation of phenylalanine to tyrosine (Scheme 1) in catabolism of phenylalanine in the liver, with tetrahydrobiopterin (BH4) supplying the two electrons needed for the reaction (1).

Which is the enzyme that hydroxylates phenylalanine to tyrosine?

Phenylalanine hydroxylase ( PAH) ( EC 1.14.16.1) is an enzyme that catalyzes the hydroxylation of the aromatic side-chain of phenylalanine to generate tyrosine.

Can a mutation in phenylalanine hydroxylase cause tyrosineuria?

Mutations in phenylalanine hydroxylase can block the conversion of phenylalanine to tyrosine. Several hundred mutations have been documented in this enzyme. Many of these mutations destroy the enzyme activity and lead to phenylketonuria.

Why is phenylalanine hydroxylase important to human health?

Research on phenylalanine hydroxylase by Seymour Kaufman led to the discovery of tetrahydrobiopterin as a biological cofactor. The enzyme is also interesting from a human health perspective because mutations in PAH, the encoding gene, can lead to phenylketonuria, a severe metabolic disorder.

How does phenylalanine hydroxylase act on dihydrobiopterin?

Yet another enzyme acts on dihydrobiopterin to restore the original form of the cofactor, which is then used in another cycle of hydroxylation. Mutations in phenylalanine hydroxylase can block the conversion of phenylalanine to tyrosine. Several hundred mutations have been documented in this enzyme.