Abstract
It is well known that human placenta contains tissue thromboplastins, which activate the blood coagulation systems.
The anticoagulant in the placenta, however, has not yet been fully clarified, because tissue thromboplastins dominate the anticoagulant activity.
We isolated an inhibitor, of the intrinsic and extrinsic coagulation systems, from the human placental microsome, of which thromboplastin activity was removed by delipidation and Con-A chromatography.
The inhibitor was purified by the following method.
The inhibitor was adsorbed on DEAE-Sephacel ion exchange column, and was eluted with stepwise increase of molar concentraion of NaCl.
The active fraction was further purified by gel filtration with Sephacryl S-300 and Sephadex G-100.
The final product showed a single band on polyacrylamide gel electrophoresis and was estimated to be approximatey 45, 000 daltons in molecular weight.
The heat and trypsin treatment suggested that the inhibitor would be a protein.
The acting point of this inhibitor on coagulation systems is unknown at present time, but the inhibitor was none of any well-known anticoagulants, such as AT-III, α2-M, α1-AT, C1-INA, heparin.
