Brain Specific Serine Protease 4 is an alias for the gene, Protease, serine 22, in humans. Other names include: Brain-specific serine protease 4; Serine protease 22; Serine protease 26; Tryptase epsilon; BSSP-4; SP001LA; hBSSP-4; protease, serine, 22. The encoded protein is an enzyme with an amino acid length of 317 and a mass of 33.7 kDa. Brain Specific Serine Protease 4 is a member of the Peptidase S1 family. This gene shares homology with other species, including: Mouse, Rat.