Involved in the metabolism of neuropeptides under 20 amino acid residues long (PubMed:2261476). Involved in cytoplasmic peptide degradation. Able to degrade the amyloid-beta precursor protein and generate amyloidogenic fragments (By similarity). Also acts as a regulator of cannabinoid signaling pathway by mediating degradation of hemopressin, an antagonist peptide of the cannabinoid receptor CNR1 (PubMed:12500972, PubMed:18077343). Preferential cleavage of bonds with hydrophobic residues at P1, P2 and P3' and a small residue at P1' in substrates of 5 to 15 residues. Binds 1 zinc ion per subunit. Monomer. Expressed abundantly in the testis. It is also found in the liver, lung and kidney. Belongs to the peptidase M3 family.