Transformation of Autoprothrombin III to Autoprothrombin C in Sodium Citrate Solution

Abstract

SummaryAll 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.