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Prostasin is a novel human serine proteinase from seminal fluid. Purification, tissue distribution, and localization in prostate gland.

1994; Elsevier BV; Volume: 269; Issue: 29 Linguagem: Inglês

10.1016/s0021-9258(17)32244-5

1083-351X

Jack X. Yu, Chao Lian, Julie Chao,

Food Allergy and Anaphylaxis Research

Anovel serine proteinase, designated as prostasin, has been purified from human seminal fluid to apparent homogeneity by DEAE-Sepharose CL-GB and aprotinin-affinity chromatography.The purified protein migrates as two close bands with an apparent molecular mass of 40 kDa on SDS-polyacrylamide gel electrophoresis under reducing conditions.It can be labeled with ['4C]diisopropyl fluorophosphate and has a PI ranging from 4.5 to 4.8.Sequence analysis reveals that the two protein bands have an identical NH,-terminal amino acid sequence which is different from any known protein sequence in the SwissPro or GenBank data base.The NH,-terminal 20-amino acid sequence shares 5 0 4 5 % identity with human a-tryptase, elastase 2A and 2B, chymotrypsin, acrosin, and the catalytic chains of hepsin, plasma kallikrein, and coagulation factor XI. Prostasin has trypsin-like activity with a pH optimum of 9.0, hydrolyzing peptidyl fluorogenic substrates: n-Pro-Phe-Arg"CA, D-Phe-Phe-Arg-MCA, D-Val-Leu-Arg"CA, and Z-Gly-Pro-ArgAFC.It is inhibited by aprotinin, antipain, leupeptin, and benzamidine.The tissue distribution of prostasin was determined by a newly developed radioimmunoassay.Linear displacement curves for immunoreactive prostasin in body fluids and tissues were parallel with the standard curve of purified prostasin, indicating their immunological identity.Immunoreactive prostasin levels were 8.61 * 0.42 pg/ml in the seminal fluid and 0.201 * 0.029 pg/ml in urine.Prostasin is present at high levels in the prostate gland (143.7 t 15.9 ng/mg protein), moderate levels (2-6 ng/mg protein) in colon, lung, kidney, pancreas, salivary gland, liver, and bronchi, but it is not detected in the brain, muscle, testis, ventricle, atrium, and aorta.Immunohistochemical localization reveals that prostasin is present in epithelial cells and ducts of the prostate gland.These studies indicate that prostasin purified from seminal fluid is a novel serine proteinase and originates from the prostate gland.Many biological processes require specific and limited proteolysis.These include removal of signal peptides from secretory proteins; processing precursors of protein hormones, growth factors, and proteinases; blood coagulation; fibrinolysis; and complement activation (Neurath, 1986).Human seminal fluid is a rich source of various proteolytic activities.Many of the proteinases in seminal fluid are involved in postejaculatory hydrolysis of proteins and semen coagulation and liquefaction.