Possible multifunctional protease. Efficiently cleaves 'bz-Phe-Arg-4-methylcoumaryl-7-amide', a kallikrein substrate, and weakly cleaves other substrates for kallikrein and trypsin. Cleaves synthetic peptides after arginine but not lysine residues. 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). About 40% of KLK11 is inactivated by internal cleavage after Arg-188. This proteolytic inactivation may be effected by plasminogen. Localized in the prostate secretory epithelium. Belongs to the peptidase S1 family. Kallikrein subfamily.