Sorting receptor that directs prohormones to the regulated secretory pathway. Acts also as a prohormone processing enzyme in neuro/endocrine cells, removing dibasic residues from the C-terminal end of peptide hormone precursors after initial endoprotease cleavage. Release of C-terminal arginine or lysine residues from polypeptides. Binds 1 zinc ion per subunit. Interacts with secretogranin III/SCG3. Associated with the secretory granule membrane through direct binding to lipid rafts in intragranular conditions. The disease is caused by variants affecting the gene represented in this entry. Belongs to the peptidase M14 family. Isoform 2 was reported to be located in the nucleus and to interact with HDAC1 and HDAC2 (PubMed:21285511). However, this work was later retracted (PubMed:30882370).