N-Acetyl-L-phenylalanine or N-Acetylphenylalanine, belongs to the class of organic compounds known as N-acyl-alpha amino acids. N-acyl-alpha amino acids are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. N-Acetyl-L-phenylalanine can also be classified as an alpha amino acid or a derivatized alpha amino acid. Technically, N-Acetyl-L-phenylalanine is a biologically available N-terminal capped form of the proteinogenic alpha amino acid L-phenylalanine. N-acetyl amino acids can be produced either via direct synthesis of specific N-acetyltransferases or via the proteolytic degradation of N-acetylated proteins by specific hydrolases. N-terminal acetylation of proteins is a widespread and highly conserved process in eukaryotes that is involved in protection and stability of proteins. About 85% of all human proteins and 68% of all yeast proteins are acetylated at their N-terminus. Several proteins from prokaryotes and archaea are also modified by N-terminal acetylation. The majority of eukaryotic N-terminal-acetylation reactions occur through N-acetyltransferase enzymes or NAT. These enzymes consist of three main oligomeric complexes NatA, NatB, and NatC, which are composed of at least a unique catalytic subunit and one unique ribosomal anchor. The substrate specificities of different NAT enzymes are mainly determined by the identities of the first two N-terminal residues of the target protein. The human NatA complex co-translationally acetylates N-termini that bear a small amino acid (A, S, T, C, and occasionally V and G). In addition to the NAT enzymes and protein-based acetylation, N-acetylation of free phenylalanine can also occur. In particular, N-Acetyl-L-phenylalanine can be biosynthesized from L-phenylalanine and acetyl-CoA by the enzyme phenylalanine N-acetyltransferase. N-Acetyl-L-phenylalanine is a potential uremic toxin and is considered as a hazardous amphipathic metabolite of phenylalanine. Many N-acetylamino acids, including N-acetylphenylalanine, are classified as uremic toxins. Uremic toxins are a diverse group of endogenously produced molecules that, if not properly cleared or eliminated by the kidneys, can cause kidney damage, cardiovascular disease and neurological deficits. N-Acetyl-L-phenylalanine appears in large amount in urine of patients with phenylketonuria (PKU), which is a human genetic disorder due to the lack of phenylalanine hydroxylase, the enzyme necessary to metabolize phenylalanine to tyrosine. N-Acetyl-L-phenylalanine is a product of enzyme phenylalanine N-acetyltransferase [EC 2.3.1.53] which is found in the phenylalanine metabolism pathway. N-Acetyl-L-phenylalanine is produced for medical, feed, and nutritional applications such as in the preparation of aspartame. Afalanine (N-Acetyl-DL-phenylalanine) is also approved for use as an antidepressant.

Metabolism and Physiological Effects of N-Acetylphenylalanine References