Formyl-L-methionine
Formyl-L-methionine is a form of methionine produced by the human body. It is found in proteins, peptides, and polypeptides as an amino acid residue. Methionine is one of the essential amino acids needed by humans. Methionine can be converted to formyl-L-methionine by the enzyme methioninase, which is found in bacteria such as Escherichia coli. The conversion of methionine to formyl-L-methionine may be important for antigen binding sites on antibodies. The N-terminal part of the protein can be recognized by antibodies, which are then able to bind to antigenic determinants on bacteria and other pathogens.