title: The interaction among protein C inhibitor, prostate-specific antigen, and the semenogelin system.
abstract: The kallikrein-like serine protease, prostate-specific antigen (PSA), is mixed in human seminal plasma with its protein substrates semenogelin (Sg) -I, Sg-II, and protein C inhibitor (PCI), which are produced in seminal vesicles. In the seminal plasma, PSA degrades Sg-I, and Sg-II, which are major components in insoluble coagula, and PCI inhibits PSA by forming a PSA-PCI complex. Digestion of seminal coagula with PSA releases PCI and PSA-PCI complex from the coagula into a soluble phase, suggesting the presence of active PCI within the coagula. PCI forms a ternary complex with PSA and Sg-II in the seminal plasma. The binding of Sg-II to PSA and PCI is influenced by pH, ionic strength, heparin, negatively charged dextran sulfate, divalent cations, and particularly by Zn 2 +. These observations suggest that binding of PCI to Sg in seminal vesicles regulates the PSA-catalyzed degradation of Sg in seminal plasma; the complex formation among PCI, PSA, and Sg is modulated by several factors in seminal plasma.
authors.affiliation: Department of Molecular Pathobiology, Mie University Graduate School of Medicine, Tsu-city, Mie, Japan. suzuki@doc.medic.mie-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kise
authors.forename: Junji
authors.initials: J
authors.lastname: Nishioka
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D046912:Multiprotein Complexes / Q000378:metabolism*; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D018046:Protein C Inhibitor / Q000378:metabolism*; D012661:Semen / Q000378:metabolism*; D029607:Seminal Vesicle Secretory Proteins / Q000378:metabolism*; D012669:Seminal Vesicles / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D018046:Protein C Inhibitor; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D017430:Prostate-Specific Antigen; D015032:Zinc