leucyl-cystinyl aminopeptidase (LNPEP, cystinyl aminopeptidase, oxytocinase, OTase, insulin-regulated membrane aminopeptidase, insulin-responsive aminopeptidase, IRAP, placental leucine aminopeptidase, P-LAP)

Function

• cleaves N-terminal amino acid, before Cys, Leu & other amino acid residues
• degrades peptide hormones
  • oxytocin
  • vasopressin
  • angiotensin 3
  • neuronal peptides in brain?
  • met-enkephalin
  • dynorphin
• binds angiotensin IV; may be angiotensin IV receptor brain
• binds tankyrases 1 & 2

Cofactor: binds 1 Zn+2 ion per subunit

Structure

• N-glycosylated
• homodimer

Compartment

• cell membrane
• resides in intracellular vesicles together with GLUT4
• may translocate to the cell surface in response to insulin &/or oxytocin

pregnancy serum form: secreted

pregnancy serum form is derived from the membrane-bound form by proteolytic processing

in brain only the membrane-bound form is found

Alternative splicing

named isoforms=3

Expression

• expressed in placenta, heart, kidney & small intestine > neuronal cells in the brain, in skeletal muscle, spleen, liver, testes & colon

More general terms

• aminopeptidase
• cell surface receptor
• glycoprotein
• metalloprotein
• oligomerizing protein

Database

• OMIM: https://mirror.omim.org/entry/151300
• UniProt: http://www.uniprot.org/uniprot/Q9UIQ6.html