a prolyl endopeptidase-like enzyme by name only; a (thio)esterase involved in mitochondrial respiratory chain function (Rosier et al.). PREPL Prolylendopeptidase-like. Prolyl oligopeptidase (EC 3.4.21.26) (also called post-proline cleaving enzyme). N-terminal domain is a 7-bladed beta-propeller. In contrast to PREP and oligopeptidase B, which require both amino- and carboxy-terminal sequences for activity, PREPL activity appeared to depend only on the carboxy-terminal domain. Deletion of PREPL was found in patients with hypotonia-cystinuria syndrome Parvari et al. (2001, 2005) Jaeken et al. (2006)