title: Semenogelin I and semenogelin II, the major gel-forming proteins in human semen, are substrates for transglutaminase.
abstract: The major seminal vesicle secreted proteins in human semen, semenogelin I and semenogelin II, interact non-covalently and via disulphide bridges to instantly form a coagulum upon ejaculation. The coagulum is liquefied after a few minutes due to the action of a prostatic serine protease, prostate-specific antigen (PSA). In contrast to rat semen, which forms an insoluble plug within minutes of expulsion, no transglutaminase-mediated cross-linking has been demonstrated in ejaculated human semen. However, we here show that semenogelin I and semenogelin II, both in seminal vesicle fluid and purified from semen, are substrates for factor XIIIa, the fibrin cross-linking transglutaminase. The cross-linking of the semenogelins, which was conformation-dependent, and the incorporation of a fluorescence-labelled amine, were visualised by SDS/PAGE and Western blot. Purified semenogelin I and semenogelin II could be cross-linked separately into complexes. Moreover, digestion of semenogelin with PSA produced fragments, some of which were cross-linked into complexes by factor XIIIa. We also found that PSA was unable to release any semenogelin fragments during exposure of the high molecular-mass complexes of cross-linked semenogelin to active PSA.
authors.affiliation: Department of Laboratory Medicine, Lund University, University Hospital, Malmö, Sweden. anders.peter@klkemi.mas.lu.se
authors.forename: A
authors.initials: A
authors.lastname: Peter
authors.forename: H
authors.initials: H
authors.lastname: Lilja
authors.forename: A
authors.initials: A
authors.lastname: Lundwall
authors.forename: J
authors.initials: J
authors.lastname: Malm
mesh_terms: D002103:Cadaverine / Q000031:analogs & derivatives / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000378:metabolism; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012661:Semen / Q000737:chemistry*; D029607:Seminal Vesicle Secretory Proteins; D012995:Solubility; D013379:Substrate Specificity; D011503:Transglutaminases / Q000378:metabolism*; D014508:Urea / Q000494:pharmacology
chemical_list: D003432:Cross-Linking Reagents; D004220:Disulfides; D005456:Fluorescent Dyes; D012739:Gonadal Steroid Hormones; D010446:Peptide Fragments; D011994:Recombinant Proteins; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; C053510:monodansylthiacadaverine; D014508:Urea; D011503:Transglutaminases; D017430:Prostate-Specific Antigen; D002103:Cadaverine; D002118:Calcium; D004229:Dithiothreitol