Enkephalinase
Enkephalinases are enzymes that degrade endogenous enkephalin opioid peptides. They include:
- Aminopeptidase N (APN)
 - Neutral endopeptidase (NEP)
 - Dipeptidyl peptidase 3 (DPP3)
 - Carboxypeptidase A6 (CPA6)
 - Leucyl/cystinyl aminopeptidase (LNPEP)
 - Angiotensin-converting enzyme (ACE)