A Simplified and Reproducible Two-Step Method for the Purification of Prostate-Specific Antigen

Prostate-specific antigen (PSA) was purified to homogeneity from human seminal plasma by ion-exchange chromatography on a CM-Sephadex C-50 and by gel filtration on a Sephacryl S-200 column. A single 33-kDa protein band appeared in SDS-PAGE. High pressure liquid chromatography (HPLC) of the purified protein produced a single peak, while isoelectric focusing demonstrated the presence of five different isoforms of this protein. The immunoreactivity of the purified PSA was checked by Western blotting. This simple two-step method can be used for a large-scale preparation of the purified PSA for the clinical tests and also for further investigative studies on the biological properties of this protein.