preferred_name: fumarate + L-cysteine => S-[(2R)-succino]-L-cysteine
preferred_name_lc: fumarate + l-cysteine => s-[(2r)-succino]-l-cysteine
label: fumarate + L-cysteine => S-[(2R)-succino]-L-cysteine
label_lc: fumarate + l-cysteine => s-[(2r)-succino]-l-cysteine