ライフサイエンスコーパス: factor VIIIa

1 by the intrinsic tenase complex (factor IXa-factor VIIIa).

2 on of factor X regardless of the presence of factor VIIIa.

3 t) of the tenase complex is mediated through factor VIIIa.

4 it alone and approached values obtained with factor VIIIa.

5 tor IXa results in its diminished binding to factor VIIIa.

6 tifies a functional role for this subunit in factor VIIIa.

7 of interaction of each activated mutant with factor VIIIa.

8 fold reduction in affinity of factor IXa for factor VIIIa.

9 an essential synergy of interactive sites in factor VIIIa.

10 in the variant protein is in its binding to factor VIIIa.

11 o the sites of factor VIII, were observed on factor VIIIa.

12 ween A2 subunit and the A1/A3-C1-C2 dimer in factor VIIIa.

13 ] both in the absence and in the presence of factor VIIIa.

14 finity interactions of the A2 subunit within factor VIIIa.

15 mately 4- to 8-fold increase in stability of factor VIIIa.

16 although the mutant interacted normally with factor VIIIa.

17 d but reduced the affinity of factor IXa for factor VIIIa.

18 n of the coagulation cofactors factor Va and factor VIIIa.

19 or Xa during the proteolytic inactivation of factor VIIIa.

20 normally both in the absence and presence of factor VIIIa.

21 ge within the A1 subunit (residues 1-372) of factor VIIIa.

22 critical for recognition and degradation of factor VIIIa.

23 th respect to their ability to interact with factor VIIIa.

24 he coagulation cofactors factor Va (FVa) and factor VIIIa.

25 unctions generates the A1 and A2 subunits of factor VIIIa.

26 mains are separate subunits in the cofactor, factor VIIIa.

27 n of factor IXa was implicated in binding to factor VIIIa.

28 Factor VIIIa, a heterotrimer of the A1, A2, and A3-C1-C2

29 ne protease, factor IXa, a protein cofactor, factor VIIIa, a phospholipid membrane, and Ca(2+).

30 The 337-372 sequence of the factor VIIIa A1 subunit contains interactive sites for b

31 or reduce (R233A) stability of the protease-factor VIIIa A2 domain interaction.

32 d type, suggesting that interaction with the factor VIIIa A2 domain was disrupted.

33 domain, which disrupts interaction with the factor VIIIa A2 domain.

34 tor IXVIIEGF1 for Factor VIIIa with a Kd for Factor VIIIa about one order of magnitude lower than tha

35 2 degrees C to 60 degrees C and the decay of factor VIIIa activity after thrombin activation were mon

36 ion was monitored using both regeneration of factor VIIIa activity and fluorescence quenching of an a

37 Factor VIIIa activity decreased as the concentration of

38 However, A1(336) was unable to reconstitute factor VIIIa activity in the presence of A2 and A3-C1-C2

39 y inhibition of intrinsic tenase (factor IXa-factor VIIIa) activity.

40 LMWH induced a modest decrease in factor IXa-factor VIIIa affinity [K(D(app))] on PL vesicles that di

41 ted a 4-fold increase in apparent factor IXa-factor VIIIa affinity and dramatically increased coagula

42 caused a substantial reduction in factor IXa-factor VIIIa affinity in the presence of C6PS that fully

43 factor IXa H92A and K241A showed factor IXa-factor VIIIa affinity similar to factor IXa wild type (W

44 cs revealed similar affinities of APC for WT factor VIIIa and 336(P4-P3')562 variant.

45 specific, high-affinity membrane binding of factor VIIIa and factor IXa, it is not known whether PS

46 activated platelets where, in the absence of factor VIIIa and factor X, annexin V reduced the number

47 In the presence of factor VIIIa and factor X, annexin V reduced the number

48 olipid membranes on binding of factor IXa to factor VIIIa and on enzymatic cleavage of the product.

49 Considering that low levels of factors VIIIa and IXa are generated during clotting in p

50 n complete activation of fXWT; activation by factors VIIIa and IXa is approximately 30% of normal act

51 e absence of thrombin-activated factor VIII (factor VIIIa), and 4.5 nM in its presence, whereas there

52 of enzyme (factor IXa), activated cofactor (factor VIIIa), and substrate (factor X) at a common loca

53 ced approximately 6-11-fold compared with WT factor VIIIa, and approached values attributed to cleava

54 are recognition sites for FX independent of factor VIIIa, and Arg150 is a specific recognition site

55 or IXa binding in the presence or absence of factor VIIIa, and factor IXa could also decrease annexin

56 sed with increasing [NaCl] in the absence of factor VIIIa, and increased with increasing [NaCl] when

57 ophobic sites on the surface of factor VIII, factor VIIIa, and their derived subunits were evaluated

58 ases the apparent affinity of factor IXa for factor VIIIa approximately 2,000-fold, and the substrate

59 the affinity of binding to platelets of both factor VIIIa ( approximately 4-fold to K(d) approximatel

60 ented 5-10% of the value observed for native factor VIIIa (approximately 200 min-1).

61 APC cleaves at two sites in factor VIIIa, Arg336, near the C terminus of the A1 subu

62 actor activity without disrupting factor IXa-factor VIIIa assembly on the PL surface.

63 d modest if any increases in K(d) values for factor VIIIa assembly.

64 After cleavage by thrombin, factor VIIIa associates with factor IXa at the surface o

65 Further proteolysis of factor VIIIa at R336 and R562 by activated protein C sub

66 This region appears critical to factor VIIIa, because proteolysis at Arg(336) by activat

67 odestly decreased the affinity of factor IXa-factor VIIIa binding in the presence of phospholipid (K(

68 a specific high-affinity site consisting of factor VIIIa bound to a high-affinity, low-capacity rece

69 ced activity of factor IXa in the absence of factor VIIIa, but the effect was due to a decreased KM r

70 FFR-FIXa; Kd = 42.4 nM), whereas cleavage of factor VIIIa by APC eliminated this property.

71 Activated Protein C (APC) inactivates factor VIIIa by cleavage at Arg(336) and Arg(562) within

72 e second assay determined the K(d) for A2 in factor VIIIa by reconstituting various A2 and fixed leve

73 actor X consists of a complex of factor IXa, factor VIIIa, Ca(2+) and a suitable phospholipid surface

74 lamide gel electrophoresis (SDS-PAGE) of the factor VIIIa cleavage reactions revealed that these resi

75 eavages are a prerequisite for expression of factor VIIIa cofactor activity.

76 gher affinity for the isolated A1 subunit of factor VIIIa compared with factor X.

77 presence of activated platelets and cofactor factor VIIIa, compared with native factor IXa (Kd(app)FI

78 VIIa-tissue factor complex or the factor IXa-factor VIIIa complex and then to function as an enzyme i

79 he system, no contribution of the factor IXa-factor VIIIa complex to factor X activation was observed

80 phospholipid/Ca(2+) and phospholipid/Ca(2+)/factor VIIIa complexes in the presence of suboptimal PS.

81 as dependent on intrinsic tenase (factor IXa-factor VIIIa) components.

82 ed in proportion to the predicted factor IXa-factor VIIIa concentration.

83 Factor VIIIa consists of subunits designated A1, A2, and

84 Factor VIIIa consists of subunits designated A1, A2, and

85 Factor VIIIa consists of three subunits designated A1, A

86 2 segment were replaced by Ala showed that a factor VIIIa D361A/D362A/D363A mutant possessed a approx

87 Time course of the factor VIIIa degradation by APC mutants suggested that t

88 ts did not influence factor Xa generation or factor VIIIa degradation over the interval in which prot

89 ified IgG from patients' serum inhibited the factor VIIIa-dependent activation of factor X.

90 hough this material was less stable than the factor VIIIa-derived material.

91 overlaps with the binding sites for LMWH and factor VIIIa, disrupting critical factor IXa-factor VIII

92 hrombin generated by factor Xa-membrane; (d) factor VIIIa dissociation/activity loss; (e) the binding

93 of synthetic phospholipid vesicles, whereas factor VIIIa E113A displayed an approximately 4-fold gre

94 , in part, to a 2-fold increased affinity of factor VIIIa E113A for the platelet membrane.

95 At each factor X concentration and constant factor VIIIa, EC50 was the free IXaNP or IXaWT concentra

96 In the presence and absence of factor VIIIa, factor IX (100 nM) lowered the K(d,appFIXa

97 In the absence of factor VIIIa, factor IXa N178A and R165A demonstrated a

98 ition correlated to functional inhibition of factor VIIIa-factor IXa (factor Xase) enzyme complex.

99 ctor VIII binding sites but less than 10% of factor VIIIa-factor IXa activating activity.

100 These results suggest that activation of the factor VIIIa-factor IXa complex can result from binding

101 rt binding of factor VIII or function of the factor VIIIa-factor IXa complex even when PE and phospha

102 onal activity is due to a requirement of the factor VIIIa-factor IXa complex for unsaturated acyl cha

103 ylserine (C6PS) increase the activity of the factor VIIIa-factor IXa complex in a biphasic manner wit

104 have utilized the catalytic activity of the factor VIIIa-factor IXa complex to report the effect of

105 The Km for activation of factor X by the factor VIIIa-factor IXa complex was 1700 nM in solution,

106 hatidyl-L-serine-containing membranes on the factor VIIIa-factor IXa complex was the accelerated rate

107 upported less than 5% normal activity of the factor VIIIa-factor IXa complex.

108 factor VIII binding sites or to activate the factor VIIIa-factor IXa complex.

109 ontaining membranes increase the kcat of the factor VIIIa-factor IXa enzyme complex by more than 1000

110 argest effect is activation of the assembled factor VIIIa-factor IXa enzyme complex.

111 ed through the assembly of intrinsic tenase (factor VIIIa/factor IXa), prothrombinase (factor Va/fact

112 at and a 30-fold increase in the affinity of factor VIIIa for factor IXa.

113 ubstrate, factor X, and the active cofactor, factor VIIIa, form a 1:1 stoichiometric complex.

114 tability values for the mutant and wild-type factor VIIIa forms.

115 ir capacity to inhibit the reconstitution of factor VIIIa from the isolated A1/A3-C1-C2 dimer and A2

116 An important negative regulator of factor VIIIa (FVIIIa) cofactor activity is A2 subunit di

117 y, where it enhances the factor Va (FVa) and factor VIIIa (FVIIIa) inactivating property of activated

118 says, we determined that R338A-FIXa's Kd for factor VIIIa (FVIIIa) was similar to that of wt-FIXa.

119 tor X (FX) requiring Ca2+, phospholipid, and factor VIIIa (FVIIIa).

120 DHG did not affect factor VIIIa half-life or chromogenic substrate cleavage

121 Although factor VIIIa improved the affinity of factor IXa for the

122 ical for the normal binding of factor IXa to factor VIIIa in the intrinsic tenase complex.

123 nteraction of IXaNP as well as of IXaWT with factor VIIIa in the presence and absence of phospholipid

124 Factor VIIIa in the presence of PCPS has no effect on fa

125 of protein S restored near original rates of factor VIIIa inactivation and cleavage at the A1 site, t

126 n system, protein S stimulates APC-catalyzed factor VIIIa inactivation by facilitating cleavage of A2

127 f human protein S, the rate of APC-dependent factor VIIIa inactivation increased several-fold and cor

128 , both cleavages contribute significantly to factor VIIIa inactivation.

129 tein S and was almost completely inactive in factor VIIIa inactivation; phospholipid binding was, how

130 rations on lipid vesicles in the presence of factor VIIIa increased the EC50,FIXa with an IC50 of 1.5

131 Factor VIIIa increased the fluorescence anisotropy of fl

132 The activation of procofactor VIII to factor VIIIa increases the affinity of binding to platel

133 rom a recent study on subunit association in factor VIIIa indicated that the A1 and A3C1C2 domains co

134 factor VIIIa, disrupting critical factor IXa-factor VIIIa interactions.

135 milar; however, in the presence of activated factor VIIIa (intrinsic tenase complex), the normal augm

136 activated variant factor IX for the cofactor factor VIIIa is 172-fold lower than normal.

137 Factor VIIIa is a heterotrimer of A1, A2, and A3-C1-C2 s

138 Factor VIIIa is a trimer of A1, A2, and A3-C1-C2 subunit

139 Factor VIIIa is a trimer of the A1, A2, and A3-C1-C2 sub

140 Additionally, factor VIIIa is cleaved by the anticoagulant serine prot

141 Factor VIIIa is comprised of A1, A2, and A3C1C2 subunits

142 Factor VIIIa is inactivated by a combination of two mech

143 d inhibits the activation of factor X by the factor VIIIa-IXa complex with a K(i) of 285 microM.

144 constitutes cofactor activity and produced a factor VIIIa-like effect on the anisotropy of Fl-FFR-FIX

145 heparin (LMWH) was independent of factor IXa-factor VIIIa membrane assembly.

146 The resultant active factor VIIIa molecule consists of three noncovalently as

147 100,000 times more efficiently when bound to factor VIIIa on a phospholipid membrane than when free i

148 nts obtained by either titrating factor X or factor VIIIa on SFLLRN-activated platelets or phospholip

149 that in the presence of TFPI the factor IXa.factor VIIIa pathway becomes essential at low factor VII

150 erefore very close to that for the activated factor VIIIa predicted in the FX-ase complex.

151 However, APC-catalyzed inactivation of factor VIIIa proceeded at a similar rate independent of

152 In contrast, factor VIIIa reconstituted with A1(37-336) showed little

153 any affinity for A2 (K(d)>2 microm), whereas factor VIIIa reconstituted with A2 plus A1(37-336)/A3-C1

154 ofactor activity ( approximately 30% that of factor VIIIa reconstituted with native A1) in a factor X

155 binant human factor VIII (rhFVIII) and human factor VIIIa (rhFVIIIa) by recombinant human activated p

156 tants for normal and variant factor IXa with factor VIIIa shows that the affinity of the activated va

157 ion of cofactor reconstitution from isolated factor VIIIa subunits revealed the presence of a functio

158 did not directly affect reassociation of the factor VIIIa subunits.

159 302 did not affect the in vitro half-life of factor VIIIa, suggesting it did not destabilize cofactor

160 IXa-PL complex was higher in the absence of factor VIIIa, suggesting that the cofactor adversely aff

161 VIII by thrombin results in a heterotrimeric factor VIIIa that spontaneously inactivates due to disso

162 Factor VIIIa, the cofactor for the factor IXa-dependent

163 In the presence of factor VIIIa, the EC50FIXa of vesicle-supported reaction

164 In the absence of factor VIIIa, the EC50FIXa' although stable to changes i

165 Factor VIIIa, the protein cofactor for factor IXa, is co

166 Factor VIIIa, the protein cofactor for factor IXa, is co

167 ence of active site-inhibited factor IXa and factor VIIIa there are two independent factor X binding

168 he specificity of both A1 and A2 subunits in factor VIIIa, thus facilitating the cleavages of both Ar

169 FFR-factor IXa was differentially altered by factor VIIIa trimers containing either A1 or A1(336).

170 its the intrinsic tenase complex (factor IXa-factor VIIIa) via interaction with a factor IXa exosite.

171 In the presence of factor VIIIa, Vmax(app) varied in proportion to the pred

172 The apparent affinity of factor IXa for factor VIIIa was 10-fold lower in the absence of phospho

173 binding of active site-blocked factor IXa to factor VIIIa was calculated from its ability to inhibit

174 X activation by intrinsic tenase (factor IXa-factor VIIIa) was investigated.

175 vidual activated protein C cleavage sites on factor VIIIa, we engineered mutations of the activated p

176 Isolated subunits of factor VIIIa were examined for their ability to accelera

177 study, residues 558-565 of the A2 subunit of factor VIIIa were implicated in binding to factor IXa.

178 Arg(336) cleavage does not fully inactivate factor VIIIa when A2 subunit dissociation is blocked.

179 factor IXa affinity for E113A and wild-type factor VIIIa when run in the presence of synthetic phosp

180 analogous to the spontaneous inactivation of factor VIIIa, which occurs via the dissociation of the A

181 reater affinity for factor IXa compared with factor VIIIa wild type in reactions run on the platelet

182 to a higher affinity of Factor IXVIIEGF1 for Factor VIIIa with a Kd for Factor VIIIa about one order

183 Reaction of the EDC-treated factor VIIIa with activated protein C (APC), which cleav

184 Reaction of factor VIIIa with EDC resulted in the formation of a cro