Studies of Heparin Binding to Antithrombin III by Crossed Immunoelectrophoresis

1979 ◽  
Vol 42 (05) ◽  
pp. 1434-1445 ◽  
Author(s):  
Trevor W Barrowcliffe
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Antithrombin Iii ◽  
Heparan Sulphate ◽  
Heparin Binding ◽  
Binding Ability ◽  
Crossed Immunoelectrophoresis ◽  
Binding Material ◽  
At Iii ◽  
Heparin Fractions

SummaryThe technique of crossed immunoelectrophoresis has been used to study the binding to purified antithrombin III (At III) of heparin and other mucopolysaccharides. The technique was unable to detect differences among samples of whole heparin from various manufacturers, but proved useful in studying the binding of heparin fractions; at the same molarities, low and high molecular weight heparin fractions displayed equal binding ability to At III. A semi-synthetic heparin analogue showed no evidence of binding to At III, but a sample of heparan sulphate did interact with At III at a concentration 3 times that of heparin. Samples of purified At III from four different manufacturers all displayed heterogeneity with respect to heparin binding. A proportion of the total At III did not bind to heparin and, in one sample, this non-binding material constituted about 40% of the total. An antiserum made against purified At III contained antibodies with different cross-reactivities against heparin bound and non-heparin bound At III.

scholarly journals The Mode of Action of CY216 and CY222 in Plasma

1992 ◽  
Vol 67 (01) ◽  
pp. 033-041 ◽  
Author(s):  
Suzette Béguin ◽  
Simone Wielders ◽  
J C Lormeau ◽  
H Coenraad Hemker
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Time Course ◽  
Antithrombin Iii ◽  
Platelet Rich Plasma ◽  
Gel Permeation Chromatography ◽  
Heparin Binding ◽  
High Affinity ◽  
Binding Material ◽  
At Iii

SummaryThree fractions of the low molecular weight heparin CY216 (fraxiparin, mean molecular weight [MMW] 5,090), with MMWs of respectively, 3,090, 4,400 and 7,910 were prepared by gel permeation chromatography. From CY222 (MMW 3,770) as well as from CY216 and its three fractions the material with high affinity to antithrombin III (AT III) was obtained by chromatography on immobilised AT III. The molecular weight distribution of each of the ten preparations thus obtained was determined by high performance liquid chromatography, while the content of AT III binding material was determined by stoichiometric titration of AT III, monitored by intrinsic fluorescence enhancement.We measured the effect of all heparins on the decay of endogenous thrombin in plasma and on the overall generation of thrombin in plasma, triggered via the extrinsic or via the intrinsic pathway. From these data we calculated the time course of prothrombin conversion, i. e. the course of factor Xa activity as expressed by prothrombinase activity.It was found that in platelet-poor plasma the anticoagulant properties of the heparins are largely dependent on their antithrombin action, which is determined by their content of high affinity material with a MW of 5,400 or higher. The specific antithrombin activity of all heparins, when expressed in terms of material with high affinity to antithrombin III (HAM) with a MW >5,400 is 13.0 min-1/(μg/ml) (range 10.5-15.9). The anticoagulant potency is not influenced by the presence of low-affinity material and hardly by material with MW <5,400.In platelet-rich plasma, however, the presence of non-AT III binding material enhances the inhibition, presumably by neutralising heparin binding material originating from activated platelets. The ultra low MW fractions (<3,400) show a similar activity in PPP and in PRP.

Binding of Heparin Fractions to von Willebrand Factor: Effect of Molecular Weight and Affinity for Antithrombin III

1994 ◽  
Vol 71 (01) ◽  
pp. 141-146 ◽  
Author(s):  
D Baruch ◽  
Nadine Ajzenberg ◽  
Cécile Denis ◽  
Paulette Legendre ◽  
Jean-Claude Lormeau ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Antithrombin Iii ◽  
Heparin Binding ◽  
Agarose Beads ◽  
Heparin Interaction ◽  
Factor Effect ◽  
Heparin Fractions ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryTo investigate the influence of the structure of heparin on its binding to vWF, we compared heparin fractions of different molecular weight (MW) or affinity for antithrombin III (ATIII). We studied the interaction of purified 125I-vWF or plasma vWF, labeled with a pool of 125I-monoclonal antibodies to vWF, with unfractionated heparin immobilized on agarose beads. Fractions were compared as competitors of these interactions and their effect was quantitated by their half-maximal inhibition (IC50). When the MW of the fractions decreased, especially below 7500, their IC50 increased, indicating that the affinity of the fractions for vWF decreased with their MW. Using heparin-derived oligosaccharides, we also demonstrated that a minimal chain length of 18 monosaccharides was required for heparin binding to vWF. In addition, different fractions with low affinity for ATIII were compared as competitors of 125-vWF binding to heparin-agarose. Despite a very low content of ATIII binding sites, some fractions retained a low IC50. Thus, heparin interaction with vWF is independent of the presence of the ATIII binding site and is mostly dependent on the length of the heparin chain. These data suggest that unfractionated heparin is a more potent inhibitor of vWF-dependent functions than low MW heparin fractions.

Antithrombin III, the Major Modulator of Intravascular Coagulation, Is Synthesized by Human Endothelial Cells

1981 ◽  
Vol 46 (02) ◽  
pp. 504-506 ◽  
Author(s):  
T K Chan ◽  
Vivian Chan
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Vascular Endothelium ◽  
Antithrombin Iii ◽  
Heparin Binding ◽  
Human Endothelial Cells ◽  
Intravascular Coagulation ◽  
Cells In Culture ◽  
Crossed Immunoelectrophoresis ◽  
At Iii

SummaryHuman endothelial cells in culture is shown to synthesize antithrombin III (At-III). The endothelial cell At-III(EC-At-III) consists of a small fraction similar to plasma At-III and a larger fraction with decreased heparin-binding as tested by crossed immunoelectrophoresis. However, both the anti-Xa and thrombin-neutralizing activities of the EC-At-III were rapid and active even in the absence of added heparin. It is concluded that the major portion was probably bound to endogenous heparin-like substance, thus accounting for its decreased exogenous heparin binding. The presence of At-III and other antithrombotic factors in the vascular endothelium offer protection against thrombosis and possibly atherosclerosis.

Effects of heparin fractions of different affinities to antithrombin III and thrombin on the inactivation of thrombin and factor Xa by antithrombin III

1984 ◽  
Vol 62 (10) ◽  
pp. 975-983 ◽  
Author(s):  
Andrew L. Cerskus ◽  
Kathy J. Birchall ◽  
Frederick A. Ofosu ◽  
Jack Hirsh ◽  
Morris A. Blajchman
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Similar Rate ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
High Affinity ◽  
Relative Contribution ◽  
Heparin Fractions

To investigate the relative contribution of heparin-binding thrombin and antithrombin III to the enhancement of the rate of inactivation of thrombin by antithrombin III, standard heparin was fractionated on matrix-linked thrombin and (or) antithrombin III. There was a good correlation between heparin affinity for antithrombin III and its ability to enhance the inactivation of thrombin and factor Xa. In addition, there was a good correlation between affinity of heparin for thrombin and its catalytic activity on the inactivation of thrombin by antithrombin III. Thus fractions with high affinity to thrombin had similar rate-enhancing activity for thrombin inactivation to that of fractions with high affinity to antithrombin III. Fractions with high affinity to both proteins were more potent than fractions with high affinity to either protein alone. No significant differences in mean molecular weight were observed among the various heparin fractions. A heparin fraction with very low affinity to thrombin and high affinity to antithrombin III was prepared by repeated fractionation of a low molecular weight heparin on the two affinity columns. This fraction had very weak rate-enhancing activity for the inactivation of thrombin by antithrombin III, but retained substantial activity for the inactivation of factor Xa. The results of these studies support the concept that, for both standard and low molecular weight heparin, the enhancement of the inactivation of thrombin by antithrombin III requires the interaction of the heparin with both thrombin and antithrombin III.

Studies Of The Heterogeneity Of Purified Antithrombin III

1981 ◽  
Author(s):  
T W Barrowcliffe ◽  
C A Eggleton ◽  
M Mahmoud
Keyword(s):  
Antithrombin Iii ◽  
Polyacrylamide Gel Electrophoresis ◽  
Collaborative Study ◽  
Gel Filtration ◽  
Factor Xa ◽  
Heparin Binding ◽  
Predisposing Factor ◽  
Binding Material ◽  
At Iii ◽  
Immunological Assays

Deficiency of antithrombin III (At III), whether hereditary or acquired, is now recognised as a major predisposing factor for the development of venous thromboembolism. Purified At III concentrates are undergoing clinical trials in various conditions associated with At III deficiency; such concentrates may be given in addition to heparin and their potency is usually assessed by heparin co-factor assays. In an international collaborative study, a reference preparation of purified At III had a lower concentration by heparin co-factor than by immunological assays and this was shown to be due to the presence of non-heparin-binding antigens. In the present study we have examined purified At III from several manufacturers by heparin co-factor (amidolytic), progressive antithrombin (clotting) and immunological assays, and their heparin-binding abilities have been studied by crossed immunoelectrophoresis and heparin-agarose affinity chromatography.There was good agreement between progressive antithrombin and immunological assays, but in some concentrates the heparin co-factor assays gave lower activity. The proportions of non-heparin-binding material varied considerably, from less than 5% to as much as 50% of the total At III antigen in some concentrates. The non-binding material isolated from a heparin column had little heparin co-factor activity, but was able to neutralise thrombin and Factor Xa. Gel filtration and polyacrylamide gel electrophoresis showed no major distinction between heparin-binding and non-binding antigens, indicating the absence of At III-protease complexes.These studies show that some At III concentrates contain substantial amounts of partially denatured molecules, in which the heparin-binding ability of the At III has been impaired but its thrombin and Xa neutralising activity left relatively intact.

Characterization Of Rabbit Antithrombin III

1981 ◽  
Author(s):  
D Estry ◽  
J C Mattson ◽  
T G Bell ◽  
G H Tishkoff
Keyword(s):  
Molecular Weight ◽  
Antithrombin Iii ◽  
Cross Reactivity ◽  
Antigenic Determinants ◽  
Heparin Binding ◽  
Sds Page ◽  
At Iii ◽  
Human Thrombin ◽  
Immunologic Assays

The rabbit is a well established model for studying the disseminated intravascular coagulation (DIC) associated with endotoxic syndromes. In order to establish the role of antithrombin III (AT III) in the modulation of DIC in the rabbit, characterization of rabbit AT III was undertaken. Rabbit antithrombin III, isolated according to modifications of the method of Thaler and Schmer, has a molecular weight comparable to that of human AT III (62,000 daltons) as measured by mobility on SDS-PAGE gels. Mixtures of rabbit and human AT III co-migrate as a single band on 7.5% SDS-PAGE gels. Rabbit AT III possesses both progressive and heparin activated (immediate) antithrombin activity in assays using human thrombin. Antisera raised against rabbit AT III demonstrates no cross reactivity with human AT III suggesting that despite physiologic and molecular weight similarities, antigenic differences are present. Incubation of rabbit antithrombin III with specific antisera, either prior to or after addition of heparin, did not alter the ability of antithrombin III to inhibit thrombin in either the immediate or progressive assays indicating that the antigenic determinants are not found in either the heparin binding or active thrombin binding sites. Crossed immunoelectrophoresis (IEP) demonstrates that antisera to rabbit AT III reacts with both free rabbit antithrombin III and AT III-thrombin complexes and can therefore be used in immunologic assays to quantitate total rabbit AT III (bound and free) and in crossed IEP to demonstrate the mobility of both free and complexed AT III.

Reactivity of a Hereditary Abnormal Antithrombin III Fraction in the Inhibition of Thrombin and Factor Xa

1980 ◽  
Vol 44 (02) ◽  
pp. 092-095 ◽  
Author(s):  
T H Tran ◽  
C Bondeli ◽  
G A Marbet ◽  
F Duckert
Keyword(s):  
Antithrombin Iii ◽  
Factor Xa ◽  
Heparin Binding ◽  
Thrombin Inhibition ◽  
Superficial Thrombophlebitis ◽  
Heparin Concentration ◽  
Heparin Binding Site ◽  
At Iii ◽  
The Difference ◽  
Inhibition Of Thrombin

SummaryTwo different AT-III fractions were purified from the plasma of a patient with recurrent superficial thrombophlebitis. The abnormal AT-III fraction (A-AT) was compared to the normal AT-III fraction (N-AT) in the inhibition of thrombin and factor Xa. Without heparin, both inactivate proteases in a similar manner and at the same rate. However, at low heparin concentration the thrombin inhibition proceeds more slowly with A-AT than with N-AT. At high heparin concentration the difference between A-AT and N-AT becomes very small. The inhibition of factor Xa follows a similar pattern. It is suggested that the heparin binding site of A-AT differs from that of N-AT resulting in a decreased heparin cofactor activity.

The Different Forms of Antithrombin III in Serum

1977 ◽  
Vol 38 (02) ◽  
pp. 0494-0503 ◽  
Author(s):  
D. S Pepper ◽  
D Banhegyi ◽  
J. D Cash
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Human Serum ◽  
Degradation Product ◽  
Antithrombin Iii ◽  
Gel Filtration ◽  
Free Form ◽  
Polymeric Form ◽  
At Iii ◽  
Human Thrombin

SummaryAntithrombin III (AT III) complexes were isolated from human serum by affinity chromatography and gel filtration. In the first step of the preparation, using heparin-agarose chromatography, we observed that the complexed form of AT III bound less strongly to the gel than the free form and that about half of the AT III was free. With further purification a 2.5 × 105 molecular weight complex was isolated. Using 125I labelled human thrombin, this complex was radioactive indicating the presence of thrombin. Only in a synthetic thrombin-AT III system was a 9 × 104 molecular weight complex detected, but not in serum. These facts suggest that in serum AT III complexes may exist in a polymeric form. Also, an AT III antigen derived from the original AT III molecule, but not complexed, was isolated which may be a degradation product.Abbreviations used: AT-III, antithrombin III. Hepes, N-2-Hydroxyethylpiperazine-N-2-Ethanesulphonic acid.

Antithrombin III Alger: A New Homozygous AT III Variant

1986 ◽  
Vol 55 (02) ◽  
pp. 218-221 ◽  
Author(s):  
A M Fischer ◽  
P Cornu ◽  
C Sternberg ◽  
F Mériane ◽  
M D Dautzenberg ◽  
...  
Keyword(s):  
Family History ◽  
Antithrombin Iii ◽  
Antigen Concentration ◽  
Crossed Immunoelectrophoresis ◽  
The Family ◽  
At Iii ◽  
Molecular Abnormality ◽  
Slow Moving ◽  
Cofactor Activity ◽  
Plasma Heparin

SummaryA qualitative abnormality of antithrombin III (AT III) was found in the plasma of a 41-year old patient. The plasmatic AT III antigen concentration was 130% and the progressive anti-F IIa and anti-F Xa activities were normal (105% and 137%). The plasma heparin cofactor activity was less than 10%, when measured by F Ila or F Xa inhibition. Crossed immunoelectrophoresis of AT III in the presence of heparin revealed in the plasma an abnormal slow-moving peak. When tested by affinity chromatography on heparin Sepharose, this abnormal AT III did not bind to heparin. Among the investigated relatives, 5 subjects had normal AT III levels, whatever the test used, the nine others having reduced levels of antithrombin heparin cofactor activity (45-61%) but normal levels of immunoreactive AT III (97-122%). Consanguinity was found in the family history. We therefore considered our patient as homozygous for an AT III molecular abnormality affecting the binding site for heparin.

Neutralisation of Heparan Sulphate and Low Molecular Weight Heparin by Protamine

1985 ◽  
Vol 53 (01) ◽  
pp. 086-089 ◽  
Author(s):  
A R Hubbard ◽  
C A Jennings
Keyword(s):  
Molecular Weight ◽  
Plasma Proteins ◽  
Low Molecular Weight Heparin ◽  
Heparan Sulphate ◽  
Activated Partial Thromboplastin Time ◽  
Weight Basis ◽  
Low Molecular Weight ◽  
Protamine Sulphate ◽  
At Iii ◽  
Reference Preparation

SummaryThe neutralisation by protamine sulphate (PS) of heparan sulphate (HS), a low molecular weight heparin (LMWH), and a reference preparation of unfractionated heparin (UH), was studied by activated partial thromboplastin time (APTT) and anti-Xa clotting assays. UH was most easily neutralised in the APTT assay by PS (on a weight for weight basis), followed by LMWH and HS. The neutralisation of APTT activity by PS closely followed the loss of activity in the anti-Xa clotting assay, when plasma was used as the source of At III. When the anti-Xa clotting assay was carried out using purified At III in place of plasma, HS and LMWH were neutralised by much lower amounts of PS and resembled UH neutralisation more closely. Resistance of HS anti-Xa activity to PS neutralisation decreased with increasing plasma dilution. The presence of bovine albumin with purified At III concentrate increased the resistance of HS to PS neutralisation. It is concluded that PS binding to UH, HS and LMWH is probably related more to their degree of sulphation than molecular weight and that non-specific interactions between PS and plasma proteins inhibit the binding of PS to HS and LMWH.

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