an S-substituted L-cysteine <=> a thiol + 2-aminoprop-2-enoate
an s-substituted l-cysteine <=> a thiol + 2-aminoprop-2-enoate
an S-substituted L-cysteine <=> a thiol + 2-aminoprop-2-enoate
an s-substituted l-cysteine <=> a thiol + 2-aminoprop-2-enoate