Dihydrobiopterin reductase
Encyclopedia
Dihydrobiopterin
is a compound produced in the synthesis of dopamine
, norepinephrine
and epinephrine
through production of the intermediate 3,4-dihydroxy phenylalanine, also known as dopa
. Phenylalanine
is converted into dopa using tetrahydrobiopterin
releasing dihydrobiopterin
and water, which is then converted back into tetrahydrobiopterin
using the NADPH-dependent enzyme dihydrobiopterin reductase. This enzyme is sometimes defective in patients with phenylketonuria
, and is treated in the same fashion, with tyrosine
supplements and a controlled diet which is lacking in phenylalanine
.
Dihydrobiopterin
Dihydrobiopterin is a compound produced in the synthesis of dopa, dopamine, norepinephrine and epinephrine. It is restored to the required cofactor tetrahydrobiopterin by dihydrobiopterin reductase....
is a compound produced in the synthesis of dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
, norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...
and epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
through production of the intermediate 3,4-dihydroxy phenylalanine, also known as dopa
Dopa
Dopa or DOPA can refer to:* L-DOPA , used in the treatment of Parkinson's disease* D-DOPA, a chemical compound related to L-DOPA* Dopa, an angel in Enochian* Deleting Online Predators Act of 2006...
. Phenylalanine
Phenylalanine
Phenylalanine is an α-amino acid with the formula C6H5CH2CHCOOH. This essential amino acid is classified as nonpolar because of the hydrophobic nature of the benzyl side chain. L-Phenylalanine is an electrically neutral amino acid, one of the twenty common amino acids used to biochemically form...
is converted into dopa using tetrahydrobiopterin
Tetrahydrobiopterin
Tetrahydrobiopterin or sapropterin is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin , melatonin, dopamine, norepinephrine ,...
releasing dihydrobiopterin
Dihydrobiopterin
Dihydrobiopterin is a compound produced in the synthesis of dopa, dopamine, norepinephrine and epinephrine. It is restored to the required cofactor tetrahydrobiopterin by dihydrobiopterin reductase....
and water, which is then converted back into tetrahydrobiopterin
Tetrahydrobiopterin
Tetrahydrobiopterin or sapropterin is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin , melatonin, dopamine, norepinephrine ,...
using the NADPH-dependent enzyme dihydrobiopterin reductase. This enzyme is sometimes defective in patients with phenylketonuria
Phenylketonuria
Phenylketonuria is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase , rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine to the amino acid tyrosine...
, and is treated in the same fashion, with tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
supplements and a controlled diet which is lacking in phenylalanine
Phenylalanine
Phenylalanine is an α-amino acid with the formula C6H5CH2CHCOOH. This essential amino acid is classified as nonpolar because of the hydrophobic nature of the benzyl side chain. L-Phenylalanine is an electrically neutral amino acid, one of the twenty common amino acids used to biochemically form...
.