title: Isolation from human seminal plasma of an abundant 16-kDa protein originating from the prostate, its identification with a 94-residue peptide originally described as beta-inhibin.
abstract: In addition to other known markers of the human prostate, it was shown that the prostatic fraction of the split ejaculate was rich in a 16-kDa protein with properties not described previously. This protein was purified from human seminal plasma using ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, and gel filtration on Sephadex G-100. The purified protein showed a single prominent spot on two-dimensional gel electrophoresis. The sequence of the first 40 amino acids that could be positively identified was identical to that of a prostatic secretory protein of 94 amino acids (PSP94) previously designated as beta-inhibin. Antibodies produced in rabbits against the purified protein were used to develop a radioimmunoassay. These antibodies appeared to recognize only the NH2-terminal portion of the native molecule since they did not react with a synthetic peptide composed of the 28 C-terminal residues. The radioimmunoassay showed that the concentration of the protein was 1320 +/- 183 micrograms/ml in the seminal plasma of adult fertile men and 1134 +/- 136 micrograms/ml in vasectomized patients. In hypertrophic and adenocarcinomatous prostates, the concentrations were 326 +/- 156 and 104 +/- 23 micrograms/ml, respectively, while values were lower than 0.060 micrograms/ml in the testis, epididymis, vas deferens and liver. The blood plasma concentration was 0.019 +/- microgram/ml in 23 asymptomatic men 45 to 65 years old and 0.115 +/- 0.036 microgram/ml in eight patients with prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D010455:Peptides / Q000097:blood / Q000302:isolation & purification*; D011467:Prostate / Q000032:analysis*; D011471:Prostatic Neoplasms / Q000097:blood; D029584:Prostatic Secretory Proteins; D011863:Radioimmunoassay; D012661:Semen / Q000032:analysis*
chemical_list: D010455:Peptides; D029584:Prostatic Secretory Proteins; C043076:beta-microseminoprotein