Kallikrein 11 (KLK11) is also known as Hippostasin, Serine protease 20, Trypsin-like protease, PRSS20, TLSP, which belongs to the peptidase S1 family and Kallikrein subfamily. KLK11 contains one peptidase S1 domain. KLK11 is expressed in brain, skin and prostate. Isoform 1 is expressed preferentially in brain. Isoform 2 is expressed in prostate. Present in seminal plasma at concentrations ranging from 2 to 37 microg/mL (at protein level). Kallikrein 11 /KLK11 is a possible multifunctional protease and efficiently cleaves 'bz-Phe-Arg-4-methylcoumaryl-7-amide', a kallikrein substrate, and weakly cleaves other substrates for kallikrein and trypsin. KLK11 cleaves synthetic peptides after arginine but not lysine residues.