L-Phenylalanine is Found in These Foods
L-Phenylalanine Health Effects
- Metabolism: Hepatic. L-phenylalanine that is not metabolized in the liver is distributed via the systemic circulation to the various tissues of the body, where it undergoes metabolic reactions similar to those that take place in the liver.
- Uses/Sources: L-phenylalanine may be helpful in some with depression. It may also be useful in the treatment of vitiligo. There is some evidence that L-phenylalanine may exacerbate tardive dyskinesia in some schizophrenic patients and in some who have used neuroleptic drugs.
- Health Effects: Phenylalanine is neurotoxic. Chronic exposure to very high levels of phenylalanine in the blood (as found in phenylketonuria, or PKU) can lead to a build up in the cerebrospinal fluid and brain, leading to seizures, organ damage and unusual posture. High phenylalnine levels are particularly dangerous for children, because it retards brain development and can cause serious learning difficulties. Complications of PKU include severe intellectual disability, brain function abnormalities, microcephaly, mood disorders, irregular motor functioning, and behavioral problems such as attention deficit hyperactivity disorder. Chronically high levels of phenylalanine are associated with at least four other inborn errors of metabolism including: Hartnup Disorder, Hyperphenylalaniemia due to guanosine triphosphate cyclohydrolase deficiency, Tyrosinemia Type 2 (or Richner-Hanhart syndrome) and Tyrosinemia Type 3 (TYRO3).
- Symptoms: Complications of PKU include severe intellectual disability, brain function abnormalities, microcephaly, mood disorders, irregular motor functioning, and behavioral problems such as attention deficit hyperactivity disorder.
- Treatment: If PKU is diagnosed early, an affected newborn can grow up with normal brain development, but only by managing and controlling phenylalanine levels through diet, or a combination of diet and medication. The diet requires severely restricting or eliminating foods high in phenylalanine, such as meat, chicken, fish, eggs, nuts, cheese, legumes, milk and other dairy products. Starchy foods, such as potatoes, bread, pasta, and corn, must be monitored. Optimal health ranges (or "target ranges") of serum phenylalanine are between 120 and 360 µmol/L, and aimed to be achieved during at least the first 10 years of life. Recently it has been found that a chiral isomer of L-phenylalanine (called D-phenylalanine) actually arrests the fibril formation by L-phenylalanine and gives rise to flakes. These flakes do not propagate further and prevent amyloid formation by L-phenylalanine. D-phenylalanine may qualify as a therapeutic molecule in phenylketonuria (A8161).
- Route of Exposure: Absorbed from the small intestine by a sodium dependent active transport process.
Mechanism of Action
|Target Name||Mechanism of Action||References|
Alkaline phosphatase, tissue-nonspecific isozyme
Large neutral amino acids transporter small subunit 2
Phenylalanine--tRNA ligase alpha subunit
Phenylalanine--tRNA ligase, mitochondrial
Phenylalanine--tRNA ligase beta subunit
Intestinal-type alkaline phosphatase
Phospholipase A-2-activating protein