N-terminal acetylases (NATs) catalyse the covalent attachment of an acetyl moiety from acetyl-CoA to the free ¦Á-amino group at the N-terminus of a protein. This irreversible modification neutralizes the positive charge at the N-terminus and makes the N-terminal residue larger and more hydrophobic, and may also play a role in membrane targeting and gene silencing. The NatB complex is found in all eukaryotic organisms, and specifically targets N-terminal L-methionine residues attached to Asn, Asp, Gln, or Glu residues at the second position. Formerly EC 2.3.1.88.
Cofactor
History
Reactions
(1) Acetyl-CoA + an N-terminal L-methionyl-L-asparaginyl-[protein] = an N-terminal N(alpha)-acetyl-L-methionyl-L-asparginyl-[protein] + CoA. (2) Acetyl-CoA + an N-terminal L-methionyl-L-glutaminyl-[protein] = an N-terminal N(alpha)-acetyl-L-methionyl-L-glutaminyl-[protein] + CoA. (3) Acetyl-CoA + an N-terminal L-methionyl-L-aspartyl-[protein] = an N-terminal N(alpha)-acetyl-L-methionyl-L-aspartyl-[protein] + CoA. (4) Acetyl-CoA + an N-terminal L-methionyl-L-glutamyl-[protein] = an N-terminal N(alpha)-acetyl-L-methionyl-L-glutamyl-[protein] + CoA.
