preferred_name: 5-oxo-L-proline + L-lysine => epsilon-(gamma-L-glutamyl)-L-lysine
preferred_name_lc: 5-oxo-l-proline + l-lysine => epsilon-(gamma-l-glutamyl)-l-lysine
label: 5-oxo-L-proline + L-lysine => epsilon-(gamma-L-glutamyl)-L-lysine
label_lc: 5-oxo-l-proline + l-lysine => epsilon-(gamma-l-glutamyl)-l-lysine