U. Tessmer et al., BIOLOGICAL-ACTIVITY OF PROSTATE-SPECIFIC ANTIGEN ISOLATED BY SODIUM DODECYL SULFATE-POLYACRYLAMIDE GEL-ELECTROPHORESIS AND ELECTROELUTION, Electrophoresis, 16(5), 1995, pp. 793-799
Human prostate-specific antigen (PSA), a 33 kDa kallikrein-like serine
protease, occurring in the prostate, in seminal plasma and in blood,
was prepared under nonreducing conditions in an enzymatically active f
orm from seminal plasma by sodium dodecyl sulfate-polyacrylamide gel e
lectrophoresis (SDS-PAGE), followed by fast copper staining, electroel
ution from gel slices and diaIysis against isotonic phosphate-buffered
saline (PBS). Enzymatic activity was demonstrated for the first time
directly by cleavage of semenogelin, one of the biological substrates
of PSA, isolated by the same procedure, i.e. SDS-PAGE and electroeluti
on, but from seminal vesicle fluid. The purified PSA formed SDS-stable
complexes with the two major extracellular protease inhibitors in blo
od, alpha(1)-antichymotrypsin (alpha(1)-ACH) and alpha(2)-macroglobuli
n (alpha(2)-M). PSA isolated under reducing conditions was enzymatical
ly inactive and could not bind to the protease inhibitors alpha(1)-ACH
and alpha(2)-M.