Rôle of Thrombin in Prothrombin Activation

1964 ◽  
Vol 12 (02) ◽  
pp. 484-488
Author(s):  
W. H Seegers ◽  
H Schröer ◽  
D Heene
Keyword(s):  
Partial Thromboplastin Time ◽  
Procoagulant Activity ◽  
Autoprothrombin C ◽  
Generation Test ◽  
Prothrombin Activation

SummaryThe partial thromboplastin time and purified thrombin were used to demonstrate the procoagulant power of thrombin. Only 0.007 μg of thrombin could be detected in prothrombin activation. Traces of thrombin and autoprothrombin C can fully account for the generation of procoagulant activity in the thromboplastin generation test. Inactivation of these two activities by antithrombin explains the disappearance of the procoagulant power in that test, so that there now remains no valid demonstration of the existence of plasma thromboplastin or of anti-plasma thromboplastin.

scholarly journals Purified Platelet Phospholipids and Blood Coagulation

Blood ◽  
1963 ◽  
Vol 22 (1) ◽  
pp. 19-34 ◽  
Author(s):  
JOHN H. FERGUSON ◽  
AARON J. MARCUS ◽  
A. JEAN ROBINSON
Keyword(s):  
Blood Coagulation ◽  
Partial Thromboplastin Time ◽  
Blood Clotting ◽  
Two Stage ◽  
End Points ◽  
End Point ◽  
Autoprothrombin C ◽  
Generation Test

Abstract Pure platelet phosphatidylserine (PS) and phosphatidylethanolamine (PE) are compared with brain cephalin (Ceph) in clotting-tests; (1) two-stage, using (a) stypven, (b) trypsin, (c) autoprothrombin-C; (2) PTT (partial thromboplastin time); (3) TGT (thromboplastin generation test); all showing "prothromboplastic" activity, except PE in the unmodified TGT. In validated bioassays (1a), log-log plots of end point clotting-times against phosphatide concentrations are rectilinear and parallel. End points related to equivalents of prothrombin-activated (EPA), or thrombin yield (ETY), make possible computation of reactivities in mixtures. Unlike brain PS ("antithromboplastic"), platelet P-lipids show no inhibitor but summate quantitatively with each other or with Ceph. Alterations in lipid reactivities include: (i) decrease during storage, (ii) increase in desoxycholate, (both assayable), (iii) anomalous ("oxidative") increase, in thromboplastic enzyme tests, invalidating bioassays. TGT’s (3) do not show (iii), but can quantitate certain reactivities. Besides suggesting the basis for a physiologic thromboplastic role of platelets, these methods offer means to explore biochemical bases of reactivities in identifiable lipids. These may be partly related to certain enzymes or intermediates in blood clotting reactions.

INTERACTION OF BOVINE AUTOPROTHROMBIN C WITH PHOSPHOLIPIDS AND DIVALENT CATIONS

1964 ◽  
Vol 42 (11) ◽  
pp. 1595-1603 ◽  
Author(s):  
Edmond R. Cole ◽  
J. L. Koppel ◽  
John H. Olwin
Keyword(s):  
Calcium Ions ◽  
Metal Ion ◽  
Phosphatidyl Ethanolamine ◽  
Divalent Cations ◽  
Complexing Agents ◽  
Autoprothrombin C ◽  
Prothrombin Activation

A thromboplastic enzyme, autoprothrombin C, can be complexed to different phospholipids and removed from solution in the form of such complexes. A technique for dissociating these complexes was developed, resulting in the recovery of the thromboplastic enzyme essentially free of phospholipid and in a higher degree of purity. Calcium ions are required for the formation of the complex, but strontium can replace calcium not only as the metal ion in the phospholipid-complexing system, but also as an autoprothrombin C cofactor in a prothrombin activation mixture. Magnesium was not effective in either system. The role of different phospholipids in the complexing phenomenon was studied and compared with the suitability of the same phospholipids as prothrombin-activating cofactors of autoprothrombin C. All phospholipid preparations studied complexed with autoprothrombin C to some degree, but the most efficient complexing agents were found to be asolectin and a commercial phosphatidyl ethanolamine preparation, both materials being among the ones which demonstrated the highest prothrombin conversion activity. Since thrombin was not complexed under the same conditions, autoprothrombin C could be isolated from commercial thrombin preparations also containing autoprothrombin C.

Role of T and B lymphocytes in inducing monocyte procoagulant activity

1993 ◽  
Vol 70 ◽  
pp. S45
Author(s):  
R.M. Lammel ◽  
M. De Carll ◽  
B. Giusti ◽  
F. Martini ◽  
M. Attanasio ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
Procoagulant Activity ◽  
T And B Lymphocytes

Fibrillar type I collagens enhance platelet-dependent thrombin generation via glycoprotein VI with direct support of α2β1 but not αIIbβ3 integrin

2005 ◽  
Vol 94 (07) ◽  
pp. 107-114 ◽  
Author(s):  
Christelle Lecut ◽  
Martine Jandrot-Perrus ◽  
Marion A. H. Feijge ◽  
Judith M. E. M. Cosemans ◽  
Johan W. M. Heemskerk
Keyword(s):  
Thrombin Generation ◽  
Type I Collagen ◽  
Platelet Rich Plasma ◽  
Procoagulant Activity ◽  
Type I ◽  
Platelet Surface ◽  
Glycoprotein Vi ◽  
Collagen Receptors ◽  
Fibrillar Collagens

SummaryThe role of collagens and collagen receptors was investigated in stimulating platelet-dependent thrombin generation. Fibrillar type-I collagens, including collagen from human heart, were most potent in enhancing thrombin generation, in a way dependent on exposure of phosphatidylserine (PS) at the platelet surface. Soluble, non-fibrillar type-I collagen required pre-activation of integrin α2β1 with Mn2+ for enhancement of thrombin generation. With all preparations, blocking of glycoprotein VI (GPVI) with 9O12 antibody abrogated the collagen-enhanced thrombin generation, regardless of the α2β1 activation state. Blockade of α2β1 alone or antagonism of autocrine thromboxane A2 and ADP were less effective. Blockade of αIIbβ3 with abciximab suppressed thrombin generation in platelet-rich plasma, but this did not abolish the enhancing effect of collagens. The high activity of type-I fibrillar collagens in stimulating GPVI-dependent procoagulant activity was confirmed in whole-blood flow studies, showing that these collagens induced relatively high expression of PS. Together, these results indicate that: i) fibrillar type-I collagen greatly enhances thrombin generation, ii) GPVI-induced platelet activation is principally responsible for the procoagulant activity of fibrillar and non-fibrillar collagens, iii) α2β1 and signaling via autocrine mediators facilitate and amplify this GPVI activity, and iv) αIIbβ3 is not directly involved in the collagen effect.

AUTOPROTHROMBIN C: A SECOND ENZYME FROM PROTHROMBIN

1962 ◽  
Vol 40 (1) ◽  
pp. 597-605 ◽  
Author(s):  
Ewa Marciniak ◽  
Walter H. Seegers
Keyword(s):  
Calcium Ions ◽  
Esterase Activity ◽  
Sodium Citrate ◽  
Citrate Solution ◽  
Tissue Extracts ◽  
End Products ◽  
Ph Range ◽  
Autoprothrombin C ◽  
Prothrombin Activation ◽  
Rapid Conversion

In addition to thrombin, there is another derivative of prothrombin which is an end product of prothrombin activation. It is an accelerator of prothrombin activation, and is called autoprothrombin C. The activity develops from purified bovine prothrombin in 25% sodium citrate solution simultaneously with thrombin. It has been separated from thrombin by chromatography on Amberlite IRC-50 under the conditions previously used for the isolation of thrombin. The fraction which separates from thrombin has esterase activity and very likely this esterase activity is associated with the autoprothrombin C molecule. Since the autoprothrombin C and the thrombin are both derived from prothrombin, at least two enzymes are the end products of prothrombin activation. Autoprothrombin C catalyzed the activation of purified prothrombin in 25% sodium citrate solution, and this function was easily inhibited with p-toluenesulphonyl-L-arginine methyl ester. Autoprothrombin C preparations were mixed with platelets, Ac-globulin, and calcium ions to obtain rapid conversion of purified prothrombin to thrombin. This activation mixture did not generate autoprothrombin C and some unspecified substance most likely needs to be added in order to obtain the autoprothrombin C activity. The activity developed together with thrombin when tissue extracts, Ac-globulin, and calcium ions were used for the activation of prothrombin. Autoprothrombin C is relatively stable over the pH range 5.5 to 8.5. It is stable up to 56 °C for 30 minutes. Plasma contains a substance that inactivates autoprothrombin C.

The role of the endothelium in changes in procoagulant activity in sepsis

1998 ◽  
Vol 187 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Toshiaki Iba ◽  
Akio Kidokoro ◽  
Yoshihiro Yagi
Keyword(s):  
Procoagulant Activity
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