InterPro domain: IPR008794

This family consists of proline racemase ( 5.1.1.4 ), 4-hydroxyproline epimerase ( 5.1.1.8 ), and trans-L-3-hydroxyproline dehydratase ( 4.2.1.77 ).

Proline racemase catalyses the interconversion of L- and D-proline in bacteria [ 1 ]. Although the mechanisms of aminoacid racemisation and epimerisation are conserved between proline racemase and hydroxyproline epimerase, substrate specificity partly rely on constraints imposed by certain residues distinctively belonging to the catalytic pocket [ 2 ]. A human proline racemase-like gene, lacking a specific cysteine residue critical for racemase activity, has been identified as a trans-3-hydroxy-L-proline dehydratase [ 3 ]. This family also contains several proteins that remain uncharacterised.

1. Energetics of proline racemase: racemization of unlabeled proline in the unsaturated, saturated, and oversaturated regimes. Biochemistry 25, 2529-37
2. Molecular and structural discrimination of proline racemase and hydroxyproline-2-epimerase from nosocomial and bacterial pathogens. PLoS ONE 2, e885
3. Identification of a human trans-3-hydroxy-L-proline dehydratase, the first characterized member of a novel family of proline racemase-like enzymes. J. Biol. Chem. 287, 21654-62