The Molecular-Mass Dependence of Dextran Sulfate Enhancement of Inactivation of Thrombin and Fibrinogen and on Factor Xa Neutralization by Antithrombin III

1989 ◽  
Vol 370 (2) ◽  
pp. 715-722 ◽  
Author(s):  
Genichiro OSHIMA
1976 ◽  
Vol 35 (02) ◽  
pp. 295-304 ◽  
Author(s):  
B Østerud ◽  
M Miller-Andersson ◽  
U Abildgaard ◽  
H Prydz

SummaryAntithrombin III, purified to homogeneity according to Polyacrylamide gel disc electrophoresis and immunoelectrophoresis, inhibited the activity of purified factor IXa and Xa, whereas factor VII was not inhibited either in the active or in the native form.Antithrombin III is the single most important inhibitor of factor Xa in plasma. Factor Xa does not, however, reduce the activity of antithrombin III against thrombin.


1980 ◽  
Vol 44 (02) ◽  
pp. 092-095 ◽  
Author(s):  
T H Tran ◽  
C Bondeli ◽  
G A Marbet ◽  
F Duckert

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.


1977 ◽  
Vol 38 (02) ◽  
pp. 0475-0485 ◽  
Author(s):  
Anna D. Borsodi ◽  
Ralph A. Bradshaw

SummaryThe plasma of individuals, hetero- or homozygous for α1-antitrypsin deficiency, contains greatly decreased amounts of antithrombin activity as assayed against factor Xa. However, heparin stimulation of the residual antithrombin activity is observed, which is comparable to that of normal plasma. Antithrombins isolated from both normal and α1-antitrypsin deficient plasma by a simplified procedure are indistinguishable in both properties and yields. The microheterogeneity observed on isoelectric focusing of both preparations can be eliminated by treatment with neuraminidase. Neither purified human antithrombin nor α1-antitrypsin, when assayed against bovine trypsin, is stimulated by heparin. These results clearly establish the unique natures of antithrombin and α1-antitrypsin and show that about 75% of the antithrombin activity measured in normal plasma is due to α1-antitrypsin. Estimates of anti thrombin III activity in normal plasma by assays dependent on enzymatic activity can probably be obtained only in the presence of heparin.


1981 ◽  
Vol 46 (04) ◽  
pp. 749-751 ◽  
Author(s):  
E Cofrancesco ◽  
A Vigo ◽  
E M Pogliani

SummaryThe ability of heparin and related glycosaminoglycans (GAGs) to accelerate the inhibition of thrombin, factor Xa and plasmin in plasma and in a purified system containing antithrombin III (At III) was studied using chromogenic peptide substrate assaysThere was a good correlation between the charge density of the mucopolysaccharides and the activities investigated. While the difference between potentiation of the antithrombin activity by GAGs in plasma and in the purified system was slight, the inhibition of factor Xa in plasma was more pronounced than in the presence of purified At III, indicating the mechanisms for GAGs-potentiated inhibition of thrombin and factor Xa are not identical.For the antiplasmin activity, there was a good correlation between the chemical structure and biological activity only in the pure system, confirming that the antithrombin-GAG complex plays a very limited role in the inactivation of plasmin in plasma.


1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.


1983 ◽  
Vol 49 (02) ◽  
pp. 109-115 ◽  
Author(s):  
M Hoylaerts ◽  
E Holmer ◽  
M de Mol ◽  
D Collen

SummaryTwo high affinity heparin fragments (A/r 4,300 and M, 3,200) were covalently coupled to antithrombin III (J. Biol. Chem. 1982; 257: 3401-3408) with an apparent 1:1 stoichiometry and a 30-35% yield.The purified covalent complexes inhibited factor Xa with second order rate constants very similar to those obtained for antithrombin III saturated with these heparin fragments and to that obtained for the covalent complex between antithrombin III and native high affinity heparin.The disappearance rates from plasma in rabbits of both low molecular weight heparin fragments and their complexes could adequately be represented by two-compartment mammillary models. The plasma half-life (t'/j) of both low Afr-heparin fragments was approximately 2.4 hr. Covalent coupling of the fragments to antithrombin III increased this half-life about 3.5 fold (t1/2 ≃ 7.7 hr), approaching that of free antithrombin III (t1/2 ≃ 11 ± 0.4 hr) and resulting in a 30fold longer life time of factor Xa inhibitory activity in plasma as compared to that of free intact heparin (t1/2 ≃ 0.25 ± 0.04 hr).


1986 ◽  
Vol 56 (03) ◽  
pp. 349-352 ◽  
Author(s):  
A Tripodi ◽  
A Krachmalnicoff ◽  
P M Mannucci

SummaryFour members of an Italian family (two with histories of venous thromboembolism) had a qualitative defect of antithrombin III reflected by normal antigen concentrations and halfnormal antithrombin activity with or without heparin. Anti-factor Xa activities were consistently borderline low (about 70% of normal). For the propositus’ plasma and serum the patterns of antithrombin III in crossed-immunoelectrophoresis with or without heparin were indistinguishable from those of normal plasma or serum. A normal affinity of antithrombin III for heparin was documented by heparin-sepharose chromatography. Affinity adsorption of the propositus’ plasma to human α-thrombin immobilized on sepharose beads revealed defective binding of the anti thrombin III to thrombin-sepharose. Hence the molecular defect of this variant appears to be at the active site responsible for binding and neutralizing thrombin, thus accounting for the low thrombin inhibitory activity.


2021 ◽  
Vol 126 (23) ◽  
Author(s):  
Debra J. Audus ◽  
Samim Ali ◽  
Artem M. Rumyantsev ◽  
Yuanchi Ma ◽  
Juan J. de Pablo ◽  
...  

1981 ◽  
Vol 197 (3) ◽  
pp. 599-609 ◽  
Author(s):  
B Casu ◽  
P Oreste ◽  
G Torri ◽  
G Zoppetti ◽  
J Choay ◽  
...  

The chemical composition and the 13C n.m.r. spectra of heparin oligosaccharides (essentially octasaccharides), having high affinity for antithrombin III and high anti-(Factor Xa) activity, prepared by three independent approaches (extraction, partial deaminative cleavage with HNO2 and partial depolymerization with bacterial heparinase), leading to different terminal residues, have been studied and compared with those of the corresponding inactive species. Combined wit chemical data, the spectra of the active oligosaccharides and of their fragmentation products afforded information on composition and sequence. The three types of active oligosaccharides were shown to have the common hexasaccharide core I-Aa-G-As*-Is-As, where I and alpha-L-idopyranosyl-uronic acid, Aa = 2-acetamido-2-deoxy-alpha-D-glucopyranose, G = beta-D-glucopyranosyl-uronic acid, Is = alpha-L-idopyranosyluronic acid 2-O-sulphate, As = 2-deoxy-2-sulphamino-alpha-D-glucopyranose 6-O-sulphate. The fourth residue (As*) is an unusually substituted amino sugar resistant to mild deamination. The 13C spectra of the active species are characterized by signals from the above atypical amino sugar, the most evident of which is at 57.7 p.p.m. These signals, compared with those of appropriate synthetic model compounds, are compatible with the recently proposed 3-O-sulphation of the residue As* [Lindahl, Bäckström, Thunberg & Leder (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 6551-6555].


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