SV-IV Peptide1-16 reduces coagulant power in normal Factor V and Factor V Leiden.
Native Factor V is an anticoagulant, but when activated by thrombin, Factor X or platelet proteases, it becomes a procoagulant. Due to these double properties, Factor V plays a crucial role in the regulation of coagulation/anticoagulation balance. Factor V Leiden (FVL) disorder may lead to thrombophilia. Whether a reduction in the activation of Factor V or Factor V Leiden may correct the disposition to thrombophilia is unknown. Therefore we tested SV-IV Peptide 1-16 (i.e. a peptide derived by seminal protein vescicle number IV, SV-IV) to assess its capacity to inhibit the procoagulant activity of normal clotting factor V or Factor V Leiden (FVL). We found that SV-IV protein has potent anti-inflammatory and immunomodulatory properties and also exerts procoagulant activity. In the present work we show that the SV-IV Peptide 1-16, incubated with plasma containing normal Factor V or FVL plasma for 5 minutes reduces the procoagulant capacity of both substances. This is an anticoagulant effect whereas SV-IV protein is a procoagulant. This activity is effective both in terms of the coagulation tests, where coagulation times are increased, and in terms of biochemical tests conducted with purified molecules, where Factor X activation is reduced. Peptide 1-16 was, in the pure molecule system, first incubated for 5 minutes with purified Factor V then it was added to the mix of phosphatidylserine, Ca2+, Factor X and its chromogenic molecule Chromozym X. We observed a more than 50% reduction in lysis of chromogenic molecule Chromozym X by Factor Xa, compared to the sample without Peptide 1-16. Such reduction in Chromozym X lysis, is explained with the reduced activation of Factor X by partial inactivation of Factor V by Peptide 1-16. Thus our study demonstrates that Peptide 1-16 reduces the coagulation capacity of Factor V and Factor V Leiden in vitro, and, in turn, causes factor X reduced activation.
D020016:Activated Protein C Resistance / Q000097:blood; D000595:Amino Acid Sequence; D001777:Blood Coagulation / Q000187:drug effects*; D005165:Factor V / Q000032:analysis; D005170:Factor X; D015951:Factor Xa; D006801:Humans; D010314:Partial Thromboplastin Time; D010446:Peptide Fragments / Q000494:pharmacology*; D029607:Seminal Vesicle Secretory Proteins / Q000494:pharmacology*
D010446:Peptide Fragments; D029607:Seminal Vesicle Secretory Proteins; C095381:factor V Leiden; D005165:Factor V; D005170:Factor X; D015951:Factor Xa