The Second Epidermal Growth Factor-like Domain of Human Factor IXa Mediates Factor IXa Binding to Platelets and Assembly of the Factor X Activating Complex†

Biochemistry ◽  
1999 ◽  
Vol 38 (28) ◽  
pp. 8948-8960 ◽  
Author(s):  
Michael Y. Wong ◽  
James A. Gurr ◽  
Peter N. Walsh
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Human Factor ◽  
Factor X ◽  
Factor Ixa ◽  
Epidermal Growth ◽  
Factor X Activating Complex

scholarly journals Tyrosine 69 of the first epidermal growth factor-like domain of human factor IX is essential for clotting activity.

1993 ◽  
Vol 268 (24) ◽  
pp. 17727-17733
Author(s):  
P.E. Hughes ◽  
G. Morgan ◽  
E.K. Rooney ◽  
G.G. Brownlee ◽  
P. Handford
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Human Factor ◽  
Factor Ix ◽  
Human Factor Ix ◽  
Epidermal Growth

scholarly journals The role of the second growth-factor domain of human factor IXa in binding to platelets and in factor-X activation

1995 ◽  
Vol 310 (2) ◽  
pp. 427-431 ◽  
Author(s):  
S S Ahmad ◽  
R Rawala ◽  
W F Cheung ◽  
D W Stafford ◽  
P N Walsh
Keyword(s):  
Growth Factor ◽  
Human Factor ◽  
Factor Ix ◽  
Factor X ◽  
Binding Studies ◽  
Factor Ixa ◽  
Equilibrium Binding ◽  
Activated Platelets ◽  
Factor Viiia ◽  
Factor X Activation

To study the structural requirements for factor IXa binding to platelets, we have carried out equilibrium binding studies with human factor IXa after replacing the second epidermal growth factor (EGF) domain by the corresponding polypeptide region of factor X. The chimeric protein, factor IX(Xegf2), and the wild-type, factor IXwt, produced in embryonic kidney cells 293 were radiolabelled with 125I and activated with factor XIa. Direct binding studies with thrombin-activated platelets showed normal stoichiometry and affinity of binding of factor IXawt in the presence of factor VIIIa (2 units/ml) and factor X (1.5 microM). However, under similar experimental conditions, factor IXa(Xegf2) was bound to a smaller number of sites (396 sites/platelet) with decreased affinity, i.e. a dissociation constant (Kd) of 1.4 nM, compared with normal factor IXa, factor IXaN (558 sites/platelet; Kd 0.67 nM), or factor IXawt (590 sites/platelet; Kd 0.61 nM). The concentrations of factor IXaN and factor IXawt required for half-maximal rates of factor-X activation were 0.63 nM and 0.7 nM, indicating a close correspondence of the Kd, app. for binding of factor IXawt to the factor-X activating complex on activated platelets to the Kd obtained in equilibrium binding studies. In contrast, kinetic parameters for factor-X activation by factor IXa(Xegf2) showed a decreased affinity (Kd 1.5 nM), in agreement with results of binding studies. These studies with factor IX(Xegf2) suggest that the EGF-2 domain may be important for specific high-affinity factor IXa binding to platelets in the presence of factor VIIIa and factor X.

scholarly journals The role of the epidermal growth factor-1 and hydrophobic stack domains of human factor IX in binding to endothelial cells

1991 ◽  
Vol 266 (14) ◽  
pp. 8797-8800 ◽  
Author(s):  
W.F. Cheung ◽  
D.L. Straight ◽  
K.J. Smith ◽  
S.W. Lin ◽  
H.R. Roberts ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Human Factor ◽  
Factor Ix ◽  
Human Factor Ix ◽  
Epidermal Growth

scholarly journals Analysis of the functions of the first epidermal growth factor-like domain of factor X.

1993 ◽  
Vol 268 (11) ◽  
pp. 8176-8180 ◽  
Author(s):  
A.R. Rezaie ◽  
P.F. Neuenschwander ◽  
J.H. Morrissey ◽  
C.T. Esmon
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Factor X ◽  
Epidermal Growth
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