N-terminal L-methionyl-[peptide] + formate => N-terminal N-formyl-L-methionyl-[peptide] + H2O
n-terminal l-methionyl-[peptide] + formate => n-terminal n-formyl-l-methionyl-[peptide] + h2o
N-terminal L-methionyl-[peptide] + formate => N-terminal N-formyl-L-methionyl-[peptide] + H2O
n-terminal l-methionyl-[peptide] + formate => n-terminal n-formyl-l-methionyl-[peptide] + h2o