... ]. The fXa dimer is 10 6 –10 7 -fold less active in prothrombin activation than monomeric fXa [ 16 ]. The opposite was true at 1 mM Ca 2+ where PS-containing membranes promoted fXa activity [ 15 ]. This finding presents two questions: first, does fXa dimerization help regulate fXa activity just after its...

..., MD 20892–8132, U.S.A. (email [email protected] ). 13 10 2004 1 12 2004 23 12 2004 23 12 2004 The Biochemical Society, London 2005 blood feeding Factor Xa heparin-binding exosite prothrombin tick saliva FXa (Factor Xa) is a vitamin K-dependent...

... evaluated the binding of β 2 GPI to PS-expressing blood platelets. Flow cytometry showed that binding of β 2 GPI is negligible at physiological ionic strength, in contrast with significant binding occurring at low ionic strength. Binding parameters of β 2 GPI and (for comparison) prothrombin were quantified...