A NEW AUTOMATED-METHOD FOR CONTINUOUS REGISTRATION OF FACTOR-VII ACTIVATION IN-VITRO - ACTIVATION IS ACCELERATED BY THE CONCENTRATION OF FACTOR-VII AND THE ACTIVITY STATE OF THE PROTEIN

When a plasma sample is exposed to tissue factor, single-chain factor VII (FVII) is gradually converted to the active two-chain form (FVIIa) . In the present study, we have constructed a measurement system, whic h allows continuous registration of the activation of FVII to FVIIa in vitro. In this system, FVII activation follows parabolic kinetic afte r an initial lag-phase. The slope of the linear phase is a measure of the protein concentration of factor VII (FVIItotal), while the length of the non-linear phase represents the velocity of FVII activation. Th e time required for complete activation of FVII is inversely related t o both FVIItotal and the relative amount of FVIIa in the sample. In fu ture studies, this new measurement system will make it possible to stu dy the process of FVII activation in different samples, and to examine how varying concentrations of exogenuous added components affect the activation process in vitro.