Results 11 to 20 of about 162,440 (195)
Localization of a Factor X Interactive Site in the A1 Subunit of Factor VIIIa [PDF]
Journal of Biological Chemistry, 1997 The protein cofactor, factor (F) VIIIa, is required for the efficient conversion of the substrate FX to FXa by the serine protease FIXa. The interaction between human FVIII (and its constituent subunits) and FX was characterized using a solid phase binding assay performed in the absence of phospholipid and FIXa. Saturable binding of FX to heterodimeric
Kirsty A. Lapan, Philip J. Fay
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Factor IXa:Factor VIIIa Interaction [PDF]
Journal of Biological Chemistry, 2001 The physiologic activator of factor X consists of a complex of factor IXa, factor VIIIa, Ca(2+) and a suitable phospholipid surface. In one study, helix 330 (162 in chymotrypsin) of the protease domain of factor IXa was implicated in binding to factor VIIIa. In another study, residues 558-565 of the A2 subunit of factor VIIIa were implicated in binding
S Paul Bajaj +6 more
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Characterization of a genetically engineered inactivation-resistant coagulation factor VIIIa [PDF]
Proceedings of the National Academy of Sciences, 1997 Individuals with hemophilia A require frequent infusion of preparations of coagulation factor VIII. The activity of factor VIII (FVIII) as a cofactor for factor IXa in the coagulation cascade is limited by its instability after activation by thrombin.
Steven W. Pipe, Randal J. Kaufman
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The A2 Subunit of Factor VIIIa Modulates the Active Site of Factor IXa [PDF]
Journal of Biological Chemistry, 1998 Factor VIIIa, the protein cofactor for factor IXa, is comprised of A1, A2, and A3-C1-C2 subunits. Isolated subunits of factor VIIIa were examined for their ability to accelerate the factor IXa-catalyzed activation of factor X. The A2 subunit enhanced the kcat for this conversion by 100-fold whereas the Km for factor X was unaffected.
Philip J. Fay, Kyoko Koshibu
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Factor VIIIa regulates substrate delivery to the intrinsic factor X‐activating complex [PDF]
The FEBS Journal, 2005 Activation of coagulation factor X (fX) by activated factors IX (fIXa) and VIII (fVIIIa) requires the assembly of the enzyme–cofactor–substrate fIXa–fVIIIa–fX complex on negatively charged phospholipid membranes. Using flow cytometry, we explored formation of the intermediate membrane‐bound binary complexes of fIXa, fVIIIa, and fX.
Mikhail A. Panteleev +4 more
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The A1 and A2 Subunits of Factor VIIIa Synergistically Stimulate Factor IXa Catalytic Activity [PDF]
Journal of Biological Chemistry, 1999 Factor VIIIa, the protein cofactor for factor IXa, is comprised of A1, A2, and A3-C1-C2 subunits. Recently, we showed that isolated A2 subunit enhanced the kcat for factor IXa-catalyzed activation of factor X by approximately 100-fold ( approximately 1 min-1), whereas isolated A1 or A3-C1-C2 subunits showed no effect on this rate (Fay, P.
Philip J. Fay +2 more
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Cleavage of Factor VIII Light Chain Is Required for Maximal Generation of Factor VIIIa Activity [PDF]
Journal of Biological Chemistry, 1995 Thrombin-catalyzed activation of heterodimeric factor VIII occurs by limited proteolysis, yielding subunits A1 and A2 derived from the heavy chain (HC) and A3-C1-C2 derived from the light chain (LC). The roles of these cleavages in the function of procoagulant activity are poorly understood.
Lisa M. Regan, Philip J. Fay
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Localization of Factor IXa and Factor VIIIa Interactive Sites [PDF]
Journal of Biological Chemistry, 1995 The contribution of the catalytic and noncatalytic domains of factor IXa to the interaction with its cofactor, factor VIIIa, was evaluated. Two proteolytic fragments of factor IXa, lacking some or all of the serine protease domain, failed to mimic the ability of factor IXa to enhance the reconstitution of factor VIIIa from isolated A1/A3-C1-C2 dimer ...
Lynn M. OʼBrien +2 more
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A3 domain residue Glu1829 contributes to A2 subunit retention in factor VIIIa [PDF]
Journal of Thrombosis and Haemostasis, 2007 Abstract Factor VIII circulates as a heterodimer composed of a heavy chain (HC) and light chain (LC). Thrombin converts factor VIII into the active cofactor, factor VIIIa, by cleaving HC into A1 and A2 subunits. While the A1 subunit maintains a stable interaction with the LC-derived A3C1C2 subunit, the A2 subunit is weakly associated in ...
Hironao Wakabayashi +3 more
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Mechanisms of Factor Xa-catalyzed Cleavage of the Factor VIIIa A1 Subunit Resulting in Cofactor Inactivation [PDF]
Journal of Biological Chemistry, 2003 Activation of factor VIII by factor Xa is followed by proteolytic inactivation resulting from cleavage within the A1 subunit (residues 1-372) of factor VIIIa. Factor Xa attacks two sites in A1, Arg(336), which precedes the highly acidic C-terminal region, and a recently identified site at Lys(36).
Keiji Nogami +2 more
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