Resident vacuolar enzyme that catalyzes the removal of amino acids from the N-terminus of peptides and proteins. Also acts as the major cargo protein of the cytoplasm-to-vacuole targeting (Cvt) pathway. The precursor form of aminopeptidase 1 (prApe1) assembles into dodecamers and the propeptide mediates the aggregation of dodecamers into higher multimers. The multimers are then recognized via the propeptide by their receptor ATG19, and ATG19 further interacts with ATG11, which tethers the APE1-ATG19 complex to the pre-autophagosomal structure (PAS). The cargo-receptor complex (also Cvt complex) is selectively enwrapped by a double-membrane structure termed the Cvt vesicle under vegetative growth conditions and by a similar but larger double-membrane structure termed the autophagosome under nitrogen starvation conditions. The Cvt vesicle or the autophagosome fuses with the vacuolar membrane and release its content in the vacuolar lumen. In the vacuole, prApe1 is processed into mature aminopeptidase 1 (mApe1). Release of an N-terminal amino acid, preferably a neutral or hydrophobic one, from a polypeptide. Aminoacyl-arylamides are poor substrates. Binds 2 Zn(2+) ions per subunit. The average amount of Zn(2+) bound at physiological metal concentrations will be lower than stoichiometric. Strongly and specifically activated by Cl(-) and Br(-), which act as positive allosteric effectors. Inactivated by metal-chelating agents. Optimum pH is 7-8.5. Homododecamer. The precursor form of aminopeptidase 1 (prApe1) assembles into dodecamers and further aggregates into higher multimers (the Ape1 complex) in the cytoplasm. The Ape1 complex is disaggregated in the vacuolar lumen, but mature aminopeptidase 1 (mApe1) retains its dodecameric form. Dodecamer assembly in the cytoplasm is essential for formation of an enzymatically active complex. If cytoplasmic homododecamerization of prApe1 is disturbed in mutants, homododecamers of mApe1 will form in the vacuole, but they are enzymatically inactive. Interacts with ATG19. Transported to the vacuole by the cytosol-to-vacuole targeting (Cvt) pathway. Synthesized in a precursor form (prApe1) that has an amino-terminal propeptide. The N-terminal extension of the 61 kDa precursor is proteolytically processed in two sequential steps. The first step involves proteinase A (PrA/PEP4) and produces a 55 kDa unstable intermediate (iAPI). The second step involves proteinase B (PrB/PRB1) and converts iAPI into the 50 kDa stable, mature enzyme (mApe1). Present with 5730 molecules/cell in log phase SD medium. Belongs to the peptidase M18 family. It is unsure whether this protein is glycosylated or not. PubMed:5147 has shown that a preparation of aminopeptidase 1 contains about 12% of conjugated carbohydrate, while PubMed:1400574 could not identify any glycosylation, which is in agreement with the fact that aminopeptidase 1 does not transit through the secretory pathway.