Furin is a protease, a proteolytic enzyme activated by substrate presentation that in humans and other animals is encoded by the FURINgene. Some proteins are inactive when they are first synthesized, and must have sections removed in order to become active. Furin cleaves these sections and activates the proteins.[5][6][7][8] It was named furin because it was in the upstream region of an oncogene known as FES. The gene was known as FUR (FES Upstream Region) and therefore the protein was named furin. Furin is also known as PACE (Paired basic Amino acid Cleaving Enzyme). A member of family S8, furin is a subtilisin-like peptidase.
^Kiefer MC, Tucker JE, Joh R, Landsberg KE, Saltman D, Barr PJ (December 1991). "Identification of a second human subtilisin-like protease gene in the fes/fps region of chromosome 15". DNA and Cell Biology. 10 (10): 757–69. doi:10.1089/dna.1991.10.757. PMID1741956.