DETECTION OF HUMAN GLANDULAR KALLIKREIN, HK2, AS ITS PRECURSOR FORM AND IN COMPLEX WITH PROTEASE INHIBITORS IN PROSTATE CARCINOMA SERUM

Forms of human glandular kallikrein (kK2) in prostate carcinoma serum were identified using monoclonal antibodies specific for hK2 and prohK 2. Recombinant mammalian hK2, prohK2, and prostate = specific antigen (PSA) were utilized to confirm the specificity of monoclonal antibodie s for hK2 and the lack of reactivity with PSA. In prostate cancer pati ent sera containing high levels of hK2 (>100 ng/ml), hK2 exists as a c omplex with alpha(1)-antichymotrypsin with a molecular weight of 90 kD a. The kallikrein also exists as a 32-kDa free form, which includes th e precursor pro form of hK2. The relative amount of complex and free h K2 varied, but in most sera examined the 32-kDa form predominated. Rec ombinant hK2 readily formed complexes with alpha(2)-macroglobulin when the two proteins were incubated together as well as when hK2 was spik ed into female serum.