Stimulating peptidase is a subclass of serine proteases with multiple physiological functions. Many pieces of evidence suggest that many kallikrein enzymes are associated with carcinogenesis, some of which may become biomarkers for novel cancers and other diseases. Stimulating peptidase associated peptidase 3, also known as PSA (prostate-specific antigen) in clinical practice, is a single chain glycoprotein, a protease synthesized in prostate epithelial cells, present in seminal plasma, and can be used for the diagnosis and monitoring of prostate cancer. It plays a role in the liquefaction process of seminal fluid, possibly through the hydrolysis of high molecular weight seminal vesicle proteins.
