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Biochem/physiol Actions

Prostate Specific Antigen (PSA), a glycoprotein of the glandular kallikrein family, is a serine protease with chymotrypsin-like enzymatic activity. Circulating PSA exists in free and protease inhibitor-bound forms. Studying the ratios of free to inhibitor-bound forms may prove valuable in the diagnosis of prostate cancer.

Prostate-specific antigen (PSA) is an androgen-regulated serine protease specifically produced by prostatic tissue and is secreted into the lumen. PSA in semen cleaves semenogelins present in the seminal coagulum. Total PSA levels are increased in serum of prostate cancer (PCa) patients. PSA functions as a potential biomarker for PCa. Serum protease inhibitors such as α1-antichymotrypsin (α1-ACT), α2-macroglobulin (α2-M) and other acute-phase proteins form irreversible complexes with circulating PSA and hinder proteolytic activity of PSA.

General description

Prostate specific antigen (PSA) is a 26kDa single-chain glycoprotein containing 237 amino acids, encoded by the kallikrein gene mapped to human chromosome 19. It is specifically expressed by human prostate tissue and is a highly abundant proteolytic enzyme expressed in the seminal fluid.

Physical form

Solution in 10 mM Tris, 0.1% sodium azide, pH 8.0