L-Phenylalanine

L-Phenylalanine is an amino acid that is used in the biosynthesis of proteins. It is essential in humans, meaning the body cannot synthesize it and thus it must be obtained from the diet. L-Phenylalanine is biologically converted into L-tyrosine, another one of the DNA-encoded amino acids. L-tyrosine in turn is converted into L-DOPA, which is further converted into dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). The conversion of L-tyrosine and L-phenylalanine is catalyzed by the enzyme phenylalanine hydroxylase.

Sources and Function

L-Phenylalanine is found in most protein-containing foods including soybeans, cheese, nuts, seeds, beef, lamb, chicken, pork, fish, eggs, dairy products, and beans. It is also available in the form of dietary supplements.

The primary function of L-Phenylalanine in the body is to be used in the production of proteins. It is also a precursor for several important substances in the body, including epinephrine, thyroid hormones, and melanin, the pigment responsible for hair and skin color.

Health Effects

L-Phenylalanine has been studied for its potential health benefits. Some research suggests that it may help improve mood and alleviate symptoms of depression, as it is a precursor to the neurotransmitters dopamine and norepinephrine. However, more research is needed to confirm these effects.

In excess amounts, L-Phenylalanine can be harmful, especially for people with the genetic disorder phenylketonuria (PKU). People with PKU lack the enzyme needed to metabolize L-Phenylalanine, leading to dangerously high levels of the amino acid in the body.

See Also

• Amino acid
• Protein biosynthesis
• Phenylketonuria

‎