Aminopeptidase that plays a central role in peptide trimming, a step required for the generation of most HLA class I- binding peptides. Peptide trimming is essential to customize longer precursor peptides to fit them to the correct length required for presentation on MHC class I molecules. Strongly prefers substrates 9-16 residues long. Rapidly degrades 13-mer to a 9-mer and then stops. Preferentially hydrolyzes the residue Leu and peptides with a hydrophobic C-terminus, while it has weak activity toward peptides with charged C-terminus. May play a role in the inactivation of peptide hormones. May be involved in the regulation of blood pressure through the inactivation of angiotensin II and/or the generation of bradykinin in the kidney. Belongs to the peptidase M1 family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: EC 3.4.11.-; Protease; Membrane protein, integral
Cellular Component: extracellular space; endoplasmic reticulum membrane; membrane; endoplasmic reticulum; endoplasmic reticulum lumen; extracellular region; integral to membrane; cytosol
Molecular Function: protein binding; interleukin-6 receptor binding; metalloexopeptidase activity; interleukin-1, Type II receptor binding; zinc ion binding; aminopeptidase activity
Biological Process: fat cell differentiation; antigen processing and presentation of peptide antigen via MHC class I; positive regulation of angiogenesis; response to bacterium; regulation of blood pressure; membrane protein ectodomain proteolysis; angiogenesis; antigen processing and presentation of endogenous peptide antigen via MHC class I; regulation of innate immune response
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.