Purification of Prostate-Specific Antigen from Human Serum by Indirect Immunosorption and Elution with a Hapten

✍ Scribed by Jochen Peter; Carlo Unverzagt; Helmut Lenz; Wolfgang Hoesel

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 112 KB
• Volume: 273
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1006/abio.1999.4215

✦ Synopsis

When isolating proteins from complex biological material by immunosorption, the nonspecific binding and elution of other proteins present in much larger concentrations than the target protein are often a general problem, preventing the isolation of a pure protein. To improve this situation we have developed a new indirect immunosorption method, which makes use of a digoxigenylated anti-analyte antibody. This antibody is linked to streptavidin-coated magnetic beads via a biotinylated anti-digoxigenin antibody. After binding of the analyte to the affinity matrix, the complex composed of analyte and digoxigenylated anti-analyte antibody is specifically eluted with a solution of digoxigenin-lysine at pH 7.3. Coelution of nonspecifically bound proteins was highly reduced as revealed by SDS-PAGE when compared to the acidic eluates of the direct immunosorption. The efficiency of the indirect immunosorption method was demonstrated with the isolation of free prostate-specific antigen (PSA) and PSA/alpha(1)-antichymotrypsin complex from human serum and subsequent analysis of the intact proteins by SDS-PAGE and MALDI-TOF-mass spectrometry.