CT20, or Protease, serine 50, is a human gene encoded by PRSS50. It may also be known as: Probable threonine protease PRSS50; Serine protease 50; Testis-specific protease-like protein 50; Cancer/testis antigen 20; Probable threonine protease PRSS50 ; testes specific protease 50; TSP50; protease, serine, 50. The encoded protein is an enzyme with an amino acid length of 385 and a mass of 43.1 kDa. CT20 is a member of the Peptidase S1 family. Homologs of this gene exist in other organisms, including: Mouse.