preferred_name: a thiol + 2-aminoprop-2-enoate => an S-substituted L-cysteine
preferred_name_lc: a thiol + 2-aminoprop-2-enoate => an s-substituted l-cysteine
label: a thiol + 2-aminoprop-2-enoate => an S-substituted L-cysteine
label_lc: a thiol + 2-aminoprop-2-enoate => an s-substituted l-cysteine