Possible multifunctional protease. Efficiently cleaves 'bz-Phe-Arg-4-methylcoumaryl-7-amide', a kallikrein substrate, and weakly cleaves other substrates for kallikrein and trypsin (By similarity). Expressed in brain and prostate (isoform 1) and prostate (isoform 2). Belongs to the peptidase S1 family. Kallikrein subfamily.