Molecular microheterogeneity of prostate specific antigen in seminal fluid by mass spectrometry.
OBJECTIVE
Prostate specific antigen (PSA) is a widely used and clinically valuable marker for prostate disease. In order to enable the development of new PSA assays and progress the understanding of the biology of PSA we have analyzed PSA in seminal plasma.


METHODS
PSA in seminal plasma from men attending a fertility clinic and healthy controls was analyzed using SDS-PAGE, Western blotting and mass spectrometry.


RESULTS
Using mass spectrometry, different forms of PSA could be identified in 1-9 bands seen on SDS-PAGE analysis of the respective sample. However, a majority of these molecular forms of PSA were not observed on Western blots. Enzymatic activity of PSA isoforms was demonstrated by sequencing data in zymogram gels. Multivariate analysis of clinical data revealed well-separated patient groups.


CONCLUSIONS
We demonstrated that PSA in seminal plasma occurs in several isoforms, yet not all were detectable using an antibody based clinical routine method. The heterogeneity of PSA expression might be of clinical significance, by an improved patient phenotyping.
Clinical Protein Science & Imaging, Dept. of Measurement Technology and Industrial Electrical Engineering, Lund University, Lund, Sweden. akos.vegvari@elmat.lth.se
Ákos
Á
Végvári
Melinda
M
Rezeli
Carina
C
Sihlbom
Jari
J
Häkkinen
Elisabet
E
Carlsohn
Johan
J
Malm
Hans
H
Lilja
Thomas
T
Laurell
György
G
Marko-Varga
D000328:Adult; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D015153:Blotting, Western; D016000:Cluster Analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007248:Infertility, Male / Q000201:enzymology / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D010449:Peptide Mapping; D017430:Prostate-Specific Antigen / Q000737:chemistry / Q000378:metabolism*; D059748:Proteolysis; D040901:Proteomics / Q000379:methods; D015203:Reproducibility of Results; D012661:Semen / Q000201:enzymology / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
D015415:Biomarkers; D007527:Isoenzymes; D017430:Prostate-Specific Antigen