preferred_name: L-threonine + L-serine => L-threonyl-L-serine + H2O
preferred_name_lc: l-threonine + l-serine => l-threonyl-l-serine + h2o
label: L-threonine + L-serine => L-threonyl-L-serine + H2O
label_lc: l-threonine + l-serine => l-threonyl-l-serine + h2o