Release of an N-terminal amino acid, cleaves before cysteine, leucine as well as other amino acids. Degrades peptide hormones such as oxytocin, vasopressin and angiotensin III, and plays a role in maintaining homeostasis during pregnancy. May be involved in the inactivation of neuronal peptides in the brain. Cleaves Met-enkephalin and dynorphin. Binds angiotensin IV and may be the angiotensin IV receptor in the brain. {ECO:0000269|PubMed:11389728, ECO:0000269|PubMed:11707427, ECO:0000269|PubMed:1731608}. This is the function of LNPEP (leucyl and cystinyl aminopeptidase, Ensembl gene identifier ENSG00000113441).