preferred_name: trans-4-hydroxy-L-proline <=> cis-4-hydroxy-D-proline
preferred_name_lc: trans-4-hydroxy-l-proline <=> cis-4-hydroxy-d-proline
label: trans-4-hydroxy-L-proline <=> cis-4-hydroxy-D-proline
label_lc: trans-4-hydroxy-l-proline <=> cis-4-hydroxy-d-proline