Purification and characterization of a new anticoagulant protein, PP27, from placenta.
It has long been known that water extracts of placenta hominis (Jahage in Korean) are effective for treating immunological and vascular diseases and is a major constituent of traditional oriental medicines. We report herein on the isolation and purification of a new type of anticoagulant protein, PP27, from human placenta. PP27 ran as a single band on SDS-PAGE with a molecular mass (Mr) of 27 kDa under denaturing conditions and chromatography on a calibrated Sepharose 4B column indicated a molecular mass of 23 kDa, a value that is similar to those of other PP4 enzymes reported to date. The isoelectric point of PP27 was pI 5.2. PP27, at doses higher than 10 microg/ml, inhibited platelet activating factor (PAF)-induced platelet activation in a dose-dependent manner. The protein was found to inhibit the coagulation time in a concentration-dependent manner. PP27, which acts as a vascular anticoagulant of annexin type, inhibits the blood clotting process by virtue of its binding of essential lipids, which is dependent on the presence of Ca2+ ions. In the presence of Ca2+ ions, PP27 combines with platelet membranes and neutralizes their procoagulant effect. Coagulation, triggered by the addition of thromboplastin/lipid mixtures, is extinguished by PP27.
Chang
Gyu-Tae
GT
Department of Biochemistry, Molecular Biology and Pediatrics, College of Oriental Medicine, Dongguk University and National Research Laboratory for Glycobiology, Sukjang-Dong 707, Kyungju, Kyungbuk 780-714, Korea.
Oh
Ju-Young
JY
Choi
Eun-Young
EY
Chung
Kang-Hyun
KH
Kim
Jang-Hyun
JH
Kim
Cheorl-Ho
CH
D000925:Anticoagulants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007526:Isoelectric Point; D008055:Lipids / Q000494:pharmacology; D008970:Molecular Weight; D010920:Placenta / Q000737:chemistry*; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013916:Thrombelastography
D000925:Anticoagulants; D008055:Lipids; D010972:Platelet Activating Factor; D011257:Pregnancy Proteins; D002118:Calcium