Summary
All reactions studied occurred in 25% sodium citrate solution. The conversion of prethrombin
to thrombin with autoprothrombin C was retarded by 3,4,4’-triaminodi-phenyl sulfone.
The compound functioned as a competitive inhibitor. Purified autoprothrombin III converted
to autoprothrombin C more rapidly when autoprothrombin C was added at zero time. Soybean
trypsin inhibitor, which neutralizes autopro-thrombin C activity, blocked the conversion
of autoprothrombin III to autoprothrom-bin C, and 3,4,4’-triaminodiphenylsulf one
inhibited the development of autoprothrombin C activity. The activation of prothrombin
in 25% sodium citrate solution consists of three main events; namely, 1. the dissociation
of prothrombin into subunits, 2. the formation of autoprothrombin C, and 3. the formation
of thrombin.
