Rat protein SV-IV (seminal vesicle protein No. 4) accelerates human blood coagulation in vitro by selective inhibition of antithrombin III.
The seminal vesicle protein No. 4 (SV-IV) secreted from the rat seminal vesicle epithelium, possesses immunosuppressive and anti-inflammatory properties and it is a potent inhibitor of platelet aggregation both in vivo and in vitro. This research aimed to investigate the possible effect of SV-IV on the process of human blood coagulation. Preliminary experiments showed that the recalcification time (RT) of platelet-poor plasma (PPP) samples, obtained from both normal subjects and patients affected by some hemorrhagic disorders, was found to be markedly reduced in the presence of micromolar amounts of SV-IV. It was demonstrated that the concentration of free antithrombin III (AT III) occurring in blood sera obtained from PPP samples recalcified in the presence of SV-IV was significantly decreased in comparison with sera obtained from PPP recalcified in the absence of SV-IV. It was also shown that PPP treatment with SV-IV significantly reduced the concentration of free AT III without affecting the levels of other plasma serine protease inhibitors, such as alpha 2-macroglobulin, alpha 1-antitrypsin and C1-inhibitor. In addition, the RT of PPP treated with a specific rabbit anti-AT III polyclonal antiserum (anti-AT III treated PPP) was not modified by SV-IV. These findings were confirmed by the observation that the addition of SV-IV into an in vitro coagulation system, containing pure fibrinogen, alpha-thrombin and AT-III, resulted in complex suppression of thrombin inhibition by AT III. No other steps of the blood clotting process (prothrombinase complex, factor XIII, fibrinogen concentration) were affected by SV-IV.
Di Micco
B
B
Department of Biochemistry and Biophysics, University of Naples, Italy.
Colonna
G
G
Porta
R
R
Metafora
S
S
D000818:Animals; D000990:Antithrombin III / Q000037:antagonists & inhibitors*; D001777:Blood Coagulation / Q000187:drug effects*; D002122:Calcium Chloride; D004305:Dose-Response Relationship, Drug; D005176:Factor XIII / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006470:Hemorrhage / Q000503:physiopathology; D006801:Humans; D066298:In Vitro Techniques; D029584:Prostatic Secretory Proteins; D011506:Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D029589:Seminal Plasma Proteins; D015843:Serpins / Q000097:blood; D013925:Thromboplastin / Q000378:metabolism
D029584:Prostatic Secretory Proteins; D011506:Proteins; D029589:Seminal Plasma Proteins; D015843:Serpins; C043076:beta-microseminoprotein; D000990:Antithrombin III; D005340:Fibrinogen; D005176:Factor XIII; D013925:Thromboplastin; D002122:Calcium Chloride