Tags: Protein.
Proprotein convertase subtilisin/kexin type 9 also known as PCSK9 is an enzyme that in humans is encoded by the PCSK9 gene. Similar genes (orthologs) are found across many species. Many enzymes including PSCK9 are inactive when they are first synthesized because they have a section of peptide chains that blocks their activity; proprotein convertases remove that section to activate the enzyme. PCSK9 has medical significance because it acts in cholesterol homeostasis.