N-Acetyl-L-methionine or N-Acetylmethionine, 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-Acetylmethionine can also be classified as an alpha amino acid or a derivatized alpha amino acid. Technically, N-Acetylmethionine is a biologically available N-terminal capped form of the proteinogenic alpha amino acid L-methionine. 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. The majority of eukaryotic N-terminal-acetylation reactions occur through N-acetyltransferase enzymes or NAT. he 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). NatA also exists in a monomeric state and can post-translationally acetylate acidic N-termini residues (D-, E-). NatB and NatC acetylate N-terminal methionine with further specificity determined by the identity of the second amino acid. N-acetylated amino acids, such as N-acetylmethionine can be released by an N-acylpeptide hydrolase from peptides generated by proteolytic degradation. In addition to the NAT enzymes and protein-based acetylation, N-acetylation of free methionine can also occur. In particular, N-Acetylmethionine can be biosynthesized from L-methionine and acetyl-CoA by the enzyme methionine N-acetyltransferase. Many N-acetylamino acids, including N-acetylmethionine are classified as uremic toxins if present in high abundance in the serum or plasma. 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.

Metabolism and Physiological Effects of N-Acetylmethionine References