May catalyze the degradation of intercellular cohesive structures in the cornified layer of the skin in the continuous shedding of cells from the skin surface. Specific for amino acid residues with aromatic side chains in the P1 position. Cleaves insulin A chain at '14-Tyr-|-Gln-15' and insulin B chain at '6-Leu-|-Cys-7', '16-Tyr-|-Leu-17', '25-Phe-|-Tyr-26' and '26-Tyr-|-Thr-27'. Could play a role in the activation of precursors to inflammatory cytokines. Cleavage of proteins with aromatic side chains in the P1 position. Inhibited by Zn2+ and Cu2+ at low micromolar concentrations. Inhibited by SERPINA12. In ovarian carcinoma, secreted and also observed at the apical membrane and in cytoplasm at the invasive front. Abundantly expressed in the skin and is expressed by keratinocytes in the epidermis. Also expressed in the brain, mammary gland, cerebellum, spinal cord and kidney. Lower levels in salivary glands, uterus, thymus, thyroid, placenta, trachea and testis. Up-regulated in ovarian carcinoma, especially late-stage serous carcinoma, compared with normal ovaries and benign adenomas (at protein level). By estrogens and glucocorticoids in a breast carcinoma cell line. Belongs to the peptidase S1 family. Kallikrein subfamily.