PEPD belongs to the peptidase M24B family of Eukaryotic-type prolidase subfamily. PEPD is a cytosolic dipeptidase that hydrolyzes dipeptides with proline or hydroxyproline at the carboxy terminus. It is important in collagen metabolism because of the high levels of imino acids. Defects in PEPD are a cause of prolidase deficiency which is an autosomal recessive disorder associated with iminodipeptiduria.