Protein S down-regulates factor Xase activity independent of activated protein C: specific binding of factor VIII(a) to protein S inhibits interactions with factor IXa
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چکیده
منابع مشابه
Regulation of factor VIIIa by human activated protein C and protein S: inactivation of cofactor in the intrinsic factor Xase.
Factor VIIIa is a trimer of A1, A2, and A3-C1-C2 subunits. Inactivation of the cofactor by human activated protein C (APC) results from preferential cleavage at Arg336 within the A1 subunit, followed by cleavage at Arg562 bisecting the A2 subunit. In the presence of human protein S, the rate of APC-dependent factor VIIIa inactivation increased several-fold and correlated with an increased rate ...
متن کاملExosite-dependent regulation of factor VIIIa by activated protein C.
Activated protein C (APC) is a natural anticoagulant serine protease in plasma that down-regulates the coagulation cascade by degrading cofactors Va and VIIIa by limited proteolysis. Recent results have indicated that basic residues of 2 surface loops known as the 39-loop (Lys37-Lys39) and the Ca2+-binding 70-80-loop (Arg74 and Arg75) are critical for the anticoagulant function of APC. Kinetics...
متن کاملInhibition of intrinsic Xase by protein S: a novel regulatory role of protein S independent of activated protein C.
OBJECTIVE Protein S is a vitamin K-dependent plasma protein that functions in the feedback regulation of thrombin generation. Our goal was to determine how protein S regulates the intrinsic pathway of blood coagulation. METHODS AND RESULTS We used plasma, including platelet-rich plasma, and in vitro methods to determine how the intrinsic pathway of blood coagulation is regulated by protein S....
متن کاملProteolytic Interactions of Factor IXa With Human Factor VI11 and Factor VIIIa
Factor IXa was shown to inactivate both factor Vlll and factor Vllla in a phospholipid-dependent reaction that could be blocked by an antifactor IX antibody. Factor IXa-catalyzed inactivation correlated with proteolytic cleavages within the A1 subunit of factor Vllla and within the heavy chain (contiguous AI-A2-6 domains) of factor VIII. Furthermore, a relatively slow conversion of factor Vlll ...
متن کاملProteolytic interactions of factor IXa with human factor VIII and factor VIIIa.
Factor IXa was shown to inactivate both factor VIII and factor VIIIa in a phospholipid-dependent reaction that could be blocked by an antifactor IX antibody. Factor IXa-catalyzed inactivation correlated with proteolytic cleavages within the A1 subunit of factor VIIIa and within the heavy chain (contiguous A1-A2-B domains) of factor VIII. Furthermore, a relatively slow conversion of factor VIII ...
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ژورنال
عنوان ژورنال: British Journal of Haematology
سال: 2008
ISSN: 0007-1048,1365-2141
DOI: 10.1111/j.1365-2141.2008.07366.x