The role of phospholipid and factor VIIIa in the activation of bovine factor X.
The kinetic parameters of bovine factor X activation by bovine factor IXa have been
determined in the absence and presence of Ca2+, thrombin-activated bovine factor VIII
(VIIIa), and phospholipid (dioleoylphosphatidylcholine/dioleoylphosphatidylserine, 75/25;
mol/mol). Factor IXa in the absence of Ca2+, factor VIIIa, and phospholipid is able to
catalyze factor X activation. The Km for factor X is 299 microM which is well above its
concentration in bovine plasma, about 0.2 microM. The Vmax of factor Xa formation is …
determined in the absence and presence of Ca2+, thrombin-activated bovine factor VIII
(VIIIa), and phospholipid (dioleoylphosphatidylcholine/dioleoylphosphatidylserine, 75/25;
mol/mol). Factor IXa in the absence of Ca2+, factor VIIIa, and phospholipid is able to
catalyze factor X activation. The Km for factor X is 299 microM which is well above its
concentration in bovine plasma, about 0.2 microM. The Vmax of factor Xa formation is …