Sensitive and specific enzymatic assay for the determination of precursor forms of prostate-specific antigen after an activation step
Background: The proteome of the serine protease prostate-specific antigen (PSA) and its enzymatic properties have been clarified only recently. We have developed a specific and sensitive method for the measurement of active PSA and used it to measure proPSA in blood. Methods: We used the synthetic peptide KGISSQY, which possesses a PSA-specific cleavage site, as substrate. To ascertain the specifi