PRELIMINARY STUDIES ON THE ISOLATION AND CHARACTERIZATION OF PREDOMINANT PROSTATIC PROTEINS

BACKGROUND. The increasing incidence of prostate cancer demands that w e give our full attention not only to the etiology and prevention of t his common type of cancer, but also to the diagnosis and prognostic co urse of this disease. In an effort to develop new prostatic tumor mark ers that could be useful to the physician at the current state of our knowledge in the diagnosis and prognosis of this disease, our laborato ries have undertaken an effort to isolate and characterize the nature of the major proteins in the normal prostate and in prostatic neoplasi a. METHODS. In this preliminary study, tissue was obtained from open p rostatic surgery in patients with a pre- and postoperative diagnosis o f benign prostatic hyperplasia. The initial fractionation and separati on of the proteins was achieved through the use of ultrafiltration of homogenates followed by SDS-PAGE. Initial analysis of four prominent p rotein bands was accomplished by amino acid sequencing, and identified by a search in GeneBank data base. RESULTS. Two proteins previously i dentified in prostatic tissue were prostate specific antigen (M(r) 26, 496) with 240 amino acid residues and beta-inhibin (M(r) 10,704) with 94-amino acid residues. A third protein was identified as human cystei ne rich protein (hCRP). This protein functions as a DNA binding protei n and has previously been postulated to contain four putative zinc fin gers and to play a fundamental role in cellular function. Ubiquitin, t he fourth major protein identified was a 76-amino acid polypeptide who se function is to target other proteins for destruction. CONCLUSIONS. hCRP and ubiquitin are reported as being found in high levels in prost atic tissue for the first time. (C) 1996 Wiley-Liss, Inc.