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.

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.

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.

AUTOPROTHROMBIN C: A SECOND ENZYME FROM PROTHROMBIN

1962 ◽  
Vol 40 (5) ◽  
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 Calcium Ions in the Activation of Blood Platelets

1975 ◽  
Author(s):  
P. Massini
Keyword(s):  
Calcium Ions ◽  
Shape Change ◽  
Divalent Cations ◽  
Blood Platelets ◽  
Clot Retraction ◽  
Release Reaction ◽  
A 23187 ◽  
External Stimuli ◽  
Stimulation Of

The plasma membrane of the resting platelet is only slightly permeable to Ca2+-ions. Stimulation of platelets with thrombin or other activators induces an increased influx of 45Ca. The influx occurs simultaneously with the release of serotonin. The “Ca influx is inhibited when the energy supply of the platelets has been interrupted. Stimulation with thrombin increases the efflux of 46Ca in platelets which have been labelled with 45Ca for 24 hours.Ionophores for divalent cations (X-537 A, A 23187) induce the release reaction, aggregation, clot retraction and rapid shape change. The release reaction does not require external Ca2+-ions whereas clot retraction depends on a Ca2+-eontaining medium.These results strongly suggest that the reactivity of platelets to external stimuli is primarily mediated by an increase of the cytoplasmic concentration of Ca2+-ions.

Autocatalysis in prothrombin activation

1962 ◽  
Vol 203 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Walter H. Seegers ◽  
Ewa Marciniak ◽  
Edmond R. Cole
Keyword(s):  
Methyl Ester ◽  
Calcium Ions ◽  
Thrombin Generation ◽  
Sodium Citrate ◽  
Citrate Solution ◽  
Intermediate Products ◽  
End Products ◽  
Autoprothrombin C ◽  
Autocatalytic Activation ◽  
Prothrombin Activation

Two enzymes, thrombin and autoprothrombin C, are derived from purified prothrombin by autocatalytic activation in 25% sodium citrate solution. The thrombin but not the autoprothrombin C activity is destroyed by diisopropylfluorophosphate. Autoprothrombin C is a procoagulant, which catalyzes the conversion of prothrombin to thrombin in a prothrombin-activating mixture consisting of calcium ions, Ac-globulin, and crude cephalin. Depending upon the amount of p-toluenesulphonyl-l-arginine methyl ester added to the prothrombin-activation mixture the thrombin generation may be retarded or inhibited completely. The view is expressed that all prothrombin activations are fundamentally autocatalytic. The end products of prothrombin activation involved are autoprothrombin C and thrombin, while the intermediate products of prothrombin activation are the autoprothrombins.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

Phospholipid-Protein Interactions in the Formation of Prothrombin Activator

1965 ◽  
Vol 14 (03/04) ◽  
pp. 431-444 ◽  
Author(s):  
E. R Cole ◽  
J. L Koppel ◽  
J. H Olwin
Keyword(s):  
Complex Formation ◽  
Protein Interactions ◽  
Calcium Ions ◽  
Fixed Number ◽  
Factor V ◽  
Clotting Factors ◽  
Number Of Binding Sites ◽  
C Complex ◽  
Autoprothrombin C

SummarySince Ac-globulin (factor V) is involved in the formation of prothrombin activator, its ability to complex with phospholipids was studied. Purified bovine Ac-globulin was complexed to asolectin, there being presumably a fixed number of binding sites on the phospholipid micelle for Ac-globulin. In contrast to the requirement for calcium ions in the formation of complexes between asolectin and autoprothrombin C, calcium ions were not required for complex formation between asolectin and Ac-globulin to occur ; in fact, the presence of calcium prevented complex formation occurring, the degree of inhibition being dependent on the calcium concentration. By treating isolated, pre-formed aso- lectin-Ac-globulin complexes with calcium chloride solutions, Ac-globulin could be recovered in a much higher state of purity and essentially free of asolectin.Complete activators were formed by first preparing the asolectin-calcium- autoprothrombin C complex and then reacting the complex with Ac-globulin. A small amount of this product was very effective as an activator of purified prothrombin without further addition of calcium or any other cofactor. If the autoprothrombin C preparation used to prepare the complex was free of traces of prothrombin, the complete activator was stable for several hours at room temperature. Stable preparations of the complete activator were centrifuged, resulting in the sedimentation of most of the activity. Experimental evidence also indicated that activator activity was highest when autoprothrombin C and Ac-globulin were complexed to the same phospholipid micelle, rather than when the two clotting factors were complexed to separate micelles. These data suggested that the in vivo prothrombin activator may be a sedimentable complex composed of a thromboplastic enzyme, calcium, Ac-globulin and phospholipid.

Partial Activation of Purified Prothrombin: Derivation of Autoprothrombin I with Use of Autoprothrombin C

1962 ◽  
Vol 07 (02) ◽  
pp. 239-248 ◽  
Author(s):  
Walter H Seegers ◽  
Edmond R Cole ◽  
Ewa Marciniak
Keyword(s):  
Calcium Ions ◽  
Platelet Factor ◽  
Stability Properties ◽  
Partial Activation ◽  
Autoprothrombin C

SummaryActivation of purified prothrombin with autoprothrombin C in the absence of calcium ions produces autoprothrombin I activity. The solubility, and stability properties of this autoprothrombin I are different from those of autoprothrombin I when obtained by activating prothrombin with calcium ions, platelet factor 3, and Ac-globulin.

The effect of complexing agents in chemical solution deposition of metal chalcogenide thin films

2021 ◽  
Author(s):  
Sucheta Sengupta ◽  
Rinki Aggarwal ◽  
Yuval Golan
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Metal Ion ◽  
Chemical Deposition ◽  
Review Article ◽  
Complexing Agents ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Metal Chalcogenide ◽  
Chalcogenide Thin Films

This review article gives an overview of different complexing agents used during chemical deposition of metal chalcogenide thin films and their role in controlling the resultant morphology by effective complexation of the metal ion.

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