Prostate specific antigen predominantly forms a complex with alpha1‐antichymotrypsin in blood. Implications for procedures to measure prostate specific antigen in serum
Background. Prostate specific antigen (PSA) is a zymogen of a 33‐kilodalton (kD) serine proteinase with extensive similarity to glandular kallikreins. The mechanism responsible for converting the zymogen into active proteinase has not been defined, but active PSA may be irreversibly inactivated in vitro by two of the major proteinase inhibitors in blood: alpha1‐antichymotrypsin and alpha2‐macroglo
