Blood coagulation Factor VII was purified 100,000-fold from fresh frozen human plasma to apparent homogeneity with a yield of 30% based on coagulation assay. The molecular weight estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 48,000. Factor VII is composed of a single polypeptide chain with the NH2-terminal sequence Ala-Asn-Ala-Phe-Leu-(Gla)-(Gla)-Leu-(Arg)-Pro. It is converted to a two-chain form (Factor VII(a)) connected by disulfide bonds by the action of Factor X(a), in the presence of phospholipids and calcium, and by Factor XII(a) without additional cofactors. This conversion is associated with a 20- to 25-fold increase in coagulation assay activity. Factors VII and VII(a) were inhibited by 15 mM diisopropyl fluorophosphate with 50% inactivation in 160 and 60 min, respectively. The presence of tissue factor and CaCl2 accelerated the inactivation by approximately 5-fold. Neither Factor VII nor VII(a) were inhibited by antithrombin III in the absence of heparin. However, with the addition of heparin, Factor VII(a) was inhibited at a rate approximately 25 times that of Factor VII.
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - Jan 1 1980|