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Factor Va-factor Xa interactions: molecular sites involved in enzyme:cofactor assembly.

Steen, Mårten LU (2002) In Scandinavian journal of clinical and laboratory investigation 62(Suppl 237). p.5-11
Abstract
The generation of thrombin by the prothrombinase complex is a key event in coagulation. In this complex, the activated form of coagulation factor V (FVa) serves as an essential cofactor to factor Xa (FXa) in the activation of prothrombin to thrombin. The enzyme FXa is virtually ineffective in the absence of its cofactor. The assembly of FXa with its cofactor FVa on negatively charged phospholipid membranes enhances its catalytic efficiency by several orders of magnitude. The non-activated procofactor factor V (FV) circulates in plasma with a domain organization of A1-A2-B-A3-C1-C2 expressing little procoagulant activity. Upon activation through limited proteolysis by either thrombin or FXa, the B-domain dissociates from FVa. After... (More)
The generation of thrombin by the prothrombinase complex is a key event in coagulation. In this complex, the activated form of coagulation factor V (FVa) serves as an essential cofactor to factor Xa (FXa) in the activation of prothrombin to thrombin. The enzyme FXa is virtually ineffective in the absence of its cofactor. The assembly of FXa with its cofactor FVa on negatively charged phospholipid membranes enhances its catalytic efficiency by several orders of magnitude. The non-activated procofactor factor V (FV) circulates in plasma with a domain organization of A1-A2-B-A3-C1-C2 expressing little procoagulant activity. Upon activation through limited proteolysis by either thrombin or FXa, the B-domain dissociates from FVa. After activation, the procoagulant activity of FVa is greatly enhanced. This report provides insight into the interaction of FV and FXa and the molecular events important in enzyme:cofactor assembly of the FXa:FVa complex. Furthermore, light is shed on the molecular events associated with the activation process, i.e. the release of the B-domain and exposure of binding sites for FXa. The assembly of FVa and FXa was studied using a set of recombinant FV mutants. The interaction between FVa and FXa on phospholipid was investigated with a functional prothrombin activation assay as well as in a novel direct binding assay in the absence of prothrombin. We found that all three thrombin cleavages in FV contribute to increasing the FXa affinity and that the B-domain in intact FV has an inhibitory effect on the FV-FXa interaction, which is important in prohibiting premature coagulation. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
phospholipids, prothrombin, factor IXa, factor VIII, factor Xa, coagulation, factor V, thrombin
in
Scandinavian journal of clinical and laboratory investigation
volume
62
issue
Suppl 237
pages
5 - 11
publisher
Taylor & Francis
external identifiers
  • wos:000180064200003
  • scopus:0036460693
ISSN
0085-591X
DOI
10.1080/003655102762377439
language
English
LU publication?
yes
id
23faa388-c98d-49be-b059-a9d363eff7b7 (old id 114478)
date added to LUP
2007-07-27 09:19:57
date last changed
2017-08-13 04:23:51
@article{23faa388-c98d-49be-b059-a9d363eff7b7,
  abstract     = {The generation of thrombin by the prothrombinase complex is a key event in coagulation. In this complex, the activated form of coagulation factor V (FVa) serves as an essential cofactor to factor Xa (FXa) in the activation of prothrombin to thrombin. The enzyme FXa is virtually ineffective in the absence of its cofactor. The assembly of FXa with its cofactor FVa on negatively charged phospholipid membranes enhances its catalytic efficiency by several orders of magnitude. The non-activated procofactor factor V (FV) circulates in plasma with a domain organization of A1-A2-B-A3-C1-C2 expressing little procoagulant activity. Upon activation through limited proteolysis by either thrombin or FXa, the B-domain dissociates from FVa. After activation, the procoagulant activity of FVa is greatly enhanced. This report provides insight into the interaction of FV and FXa and the molecular events important in enzyme:cofactor assembly of the FXa:FVa complex. Furthermore, light is shed on the molecular events associated with the activation process, i.e. the release of the B-domain and exposure of binding sites for FXa. The assembly of FVa and FXa was studied using a set of recombinant FV mutants. The interaction between FVa and FXa on phospholipid was investigated with a functional prothrombin activation assay as well as in a novel direct binding assay in the absence of prothrombin. We found that all three thrombin cleavages in FV contribute to increasing the FXa affinity and that the B-domain in intact FV has an inhibitory effect on the FV-FXa interaction, which is important in prohibiting premature coagulation.},
  author       = {Steen, Mårten},
  issn         = {0085-591X},
  keyword      = {phospholipids,prothrombin,factor IXa,factor VIII,factor Xa,coagulation,factor V,thrombin},
  language     = {eng},
  number       = {Suppl 237},
  pages        = {5--11},
  publisher    = {Taylor & Francis},
  series       = {Scandinavian journal of clinical and laboratory investigation},
  title        = {Factor Va-factor Xa interactions: molecular sites involved in enzyme:cofactor assembly.},
  url          = {http://dx.doi.org/10.1080/003655102762377439},
  volume       = {62},
  year         = {2002},
}