Which enzyme is required for the metabolism of phenylalanine?
Phenylalanine hydroxylase (PheH), a liver enzyme that catalyzes the hydroxylation of excess phenylalanine in the diet to tyrosine, is activated by phenylalanine.
How is phenylalanine metabolized?
Phenylalanine is metabolized into acetoacetic acid and fumaric acid via tyrosine. A tyrosine metabolite, DOPA, is converted into the neurotransmitters epinephrine and norepinephrine. By this metabolism, the concentration of phenylalanine in the blood is elevated.
What amino acid is similar to phenylalanine?
Substitutions: As Phenylalanine is an aromatic, hydrophobic, amino acid, it prefers substitution with other amino acids of the same type (see above). It particularly prefers to exchange with Tyrosine, which differs only in that it contains a hydroxyl group in place of the ortho hyddrogen on the benzene ring.
What amino acid becomes essential when phenylalanine is lacking in the diet?
Persons with phenylketonuria (PKU) cannot synthesize tyrosine from phenylalanine because of a severe deficiency of the hepatic enzyme phenylalanine hydroxylase (phenylalanine 4-monooxygenase). Therefore, in these persons, tyrosine is an essential amino acid.
What enzyme that converts phenylalanine to tyrosine?
Phenylalanine hydroxylase
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.
How do you increase phenylalanine?
Instead, eating a variety of protein-rich foods throughout the day will provide you with all the phenylalanine you need, along with other essential amino acids and nutrients. Many foods, including soy products, eggs, seafood, and meats, contain phenylalanine.
What does the buildup of phenylalanine cause?
A dangerous buildup of phenylalanine can develop when a person with PKU eats protein-rich foods, such as milk, cheese, nuts or meat, and even grains such as bread and pasta, or eats aspartame, an artificial sweetener. This buildup of phenylalanine results in damage to nerve cells in the brain.
What bonds can phenylalanine form?
So, in Phe’s ring, each carbon forms a sigma bond with a hydrogen and sigma bonds with the carbons on either side of it.
Is Arginine an essential amino acid?
For young organisms arginine is an essential amino acid for optimal growth and development, and must therefore be provided in the diet. For adults, arginine is a conditionally essential amino acid, especially in such conditions as trauma, burn injury, small-bowel resection, and renal failure.
What is a phenylalanine restricted diet?
Foods such as meat, fish, eggs, milk, cheese, nuts and pulses are excluded as they contain high levels of phenylalanine. Vegetables and fruit are allowed in measured amounts only! Special low protein bread, pasta, biscuits and flour are used to supplement the diet and ensure adequate calorie intake.
Which is better tyrosine or phenylalanine?
Dietary supplement: Sold as nutritional supplements for their reputed analgesic and antidepressant effects. Phenylalanine is better absorbed than tyrosine and may cause fewer headaches.