The protein encoded by this gene belongs to the subtilisin-like proprotein convertase family. The members of this family are proprotein convertases that process latent precursor proteins into their biologically active products. This encoded protein is a type I proinsulin-processing enzyme that plays a key role in regulating insulin biosynthesis. It is also known to cleave proopiomelanocortin, prorenin, proenkephalin, prodynorphin, prosomatostatin and progastrin. Mutations in this gene are thought to cause obesity. This encoded protein is associated with carcinoid tumors. Mutations in this gene have been associated with susceptibility to obesity and proprotein convertase 1/3 deficiency. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Apr 2010]