Kallikrein-related peptidase 9 (KLK9)

Kallikrein-related peptidase 9 (KLK9) is a glycosylated serine protease belonging to the kallikrein family, encoded by the KLK9 gene on chromosome 19. KLK9 is characterized by chymotrypsin-like serine protease activity, with a notable preference for cleaving peptide bonds at tyrosine residues in substrates[1][7]. Its expression is tissue-specific and regulated by steroid hormones, with highest levels found in the thymus, mammary gland, testis, brain, salivary gland, ovary, prostate, trachea, spinal cord, cerebellum, and skin[2][3]. KLK9 may play roles in extracellular protein degradation, tissue remodeling, and regulation of local physiological processes. Clinically, KLK9 has gained attention as a potential biomarker for early ovarian and breast cancer detection and prognosis, based on its hormone-regulated expression and association with tumor biology[2][3]. While KLK9 itself is not currently targeted by specific drugs, its family of enzymes is implicated in various pathological processes. Research into therapeutic targeting, safety, and clinical utility is ongoing, but no KLK9-specific drugs or standardized biomarker panels are established as of the present[3][9]. Alternative names, molecular classification, and functional details are standardized as recommended, with current knowledge reflecting its status as a validated enzyme and potential but not yet established therapeutic target.

Other names

Kallikrein-9KLK9KLK-L3Kallikrein-like protein 3KLKL3kallikrein-9kallikrein-like protein 3

No drugs with characterized mechanisms of action targeting KLK9 are listed. The enzyme's activity may be modulated indirectly by therapies affecting steroid hormones, given its regulation by these hormones[2][3].