(4S)-4-Hydroxy-L-proline; (2S,4S)-4-Hydroxyproline; (S)-Allo-hydroxyproline; (2S,4S)-4-Hydroxypyrrolidine-2-carboxylic Acid; L-Allohydroxyproline; cis-4-Hydroxyproline; cis-Hydroxyproline;

Hydroxyprolines are valuable chiral building blocks for organic synthesis of pharmaceuticals. Several microorganisms producing proline trans-4- and cis-3-hydroxylase were discovered and these enzymes were applied to the industrial production of trans-4- and cis-3-hydroxy-L-proline.