preferred_name: an alpha-(gamma-L-glutamyl)-L-amino acid => 5-oxo-L-proline + an L-alpha-amino acid
preferred_name_lc: an alpha-(gamma-l-glutamyl)-l-amino acid => 5-oxo-l-proline + an l-alpha-amino acid
label: an alpha-(gamma-L-glutamyl)-L-amino acid => 5-oxo-L-proline + an L-alpha-amino acid
label_lc: an alpha-(gamma-l-glutamyl)-l-amino acid => 5-oxo-l-proline + an l-alpha-amino acid