Proprotein Convertase 1, also known as PCSK1, PC1 or PC3, is a serine protease in the Furin family. Autocatalytic processing results in the removal of the pro peptide as well as a region from the C-terminus, which leads to the production of the most active 66 kDa form. PCSK1 is predominantly expressed in endocrine and neural cells and is stored in dense-core secretory vesicles, PCSK1 processes several endocrine and neural prohormones, including opiomelanocortin, somatostatin, enkephalin, insulin, dynorphin, and thyrotropin-releasing hormone. PCSK1 mutations are assiciated with obesity and impaired prohormone processing.
