label: 5-L-glutamyl amino acid + an N-terminal L-alpha-aminoacyl-[peptide] => an N-terminal (5-L-glutamyl)-[peptide] + an alpha-amino acid
label_lc: 5-l-glutamyl amino acid + an n-terminal l-alpha-aminoacyl-[peptide] => an n-terminal (5-l-glutamyl)-[peptide] + an alpha-amino acid