Transmembrane protease, serine 11B is a human gene encoded by the symbol, TMPRSS11B. It may also be known as: Transmembrane protease serine 11B; Airway trypsin-like protease 5; Transmembrane protease serine 11B . The encoded protein is an enzyme with an amino acid length of 416 and a mass of 46.3 kDa. Other isoforms may exist. Transmembrane protease, serine 11B is a member of the Peptidase S1 family. Homologs of this gene exist in other organisms, including: Mouse, Rat.