scholarly journals The structure of heparin oligosaccharide fragments with high anti-(factor Xa) activity containing the minimal antithrombin III-binding sequence Chemical and13C nuclear-magnetic-resonance studies

1981 ◽  
Vol 197 (3) ◽  
pp. 599-609 ◽  
Author(s):  
B Casu ◽  
P Oreste ◽  
G Torri ◽  
G Zoppetti ◽  
J Choay ◽  
...  
Keyword(s):  
Uronic Acid ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Amino Sugar ◽  
Active Species ◽  
Model Compounds ◽  
High Affinity ◽  
The Common ◽  
Binding Sequence ◽  
Heparin Oligosaccharides

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].

IS PENTASACCHARIDE THE SMALLEST HEPARIN OLIGOSACCHARIDE WITH BINDING AFFINITY TO ANTITHROMBIN III ? AN OVERVIEW

1987 ◽  
Author(s):  
J Mardiguian
Keyword(s):  
Aqueous Medium ◽  
Uronic Acid ◽  
Antithrombin Iii ◽  
Specific Binding ◽  
Factor Xa ◽  
Benzyl Ester ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Convincing Data

The binding of heparin to antithrombin III is ascribed to the presence in the heparin molecule of a specific binding site which contains a typical 3-0- sulfate group located on a glucosamine residue. It has been postulated that the smallest heparin oligosaccharide capable of high affinity binding to antithrombin III and eliciting anti-factor Xa activity is a pentasaccharide containing three glucosamine units and two uronic acid residues. Such a pentasaccharide has been recently isolated after chemical depolymerization of pig mucosal heparin and its structure found to be very close to that of a synthetic pentasaccharide prepared by other investigators. However no convincing data have, so far, excluded the possibility that an oligosaccharide composed of less than five sugar units could not be able to bind to antithrombinlll and to elicit anti-factor Xa activity. We report now the isolation of new oligosaccharides obtained by beta-eliminative chemical depolymerization of heparin using three different procedures : depolymerization of heparin benzyl ester (1) in aqueous medium and (2) in non-aqueous medium: (3) alcaline depolymerization of a periodate oxydized acetyl heparin. The data reported show that the high affinity oligosaccharides isolated after affinity chromatography on immobilized antithrombin III are distinct from the previously isolated pentasaccharide and that there is some evidence that these are tetrasaccharides resulting from the cleavage of the non reducing end of the heparin molecule

scholarly journals The effect of Ca2+, phospholipid and factor V on the anti-(factor Xa) activity of heparin and its high-affinity oligosaccharides

1987 ◽  
Vol 243 (1) ◽  
pp. 31-37 ◽  
Author(s):  
T W Barrowcliffe ◽  
S J Havercroft ◽  
G Kemball-Cook ◽  
U Lindahl
Keyword(s):  
Protective Effect ◽  
Unfractionated Heparin ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Free Enzyme ◽  
Factor V ◽  
High Affinity ◽  
Heparin Fractions ◽  
Heparin Oligosaccharides ◽  
Bovine Factor

The influence of Ca2+, phospholipid and Factor V was determined on the rate of inactivation of Factor Xa by antithrombin III, in the absence and in the presence of unfractionated heparin and of three high-affinity heparin oligosaccharides in the Mr range 1500-6000. In the absence of heparin the addition of Ca2+, phospholipid and Factor V caused a 4-fold decrease in rate of inactivation of Factor Xa. As concentrations of unfractionated heparin were increased the protective effect of Ca2+/phospholipid/Factor V was gradually abolished, and at a concentration of 2.4 nM there were no differences in rates of neutralization of Factor Xa in the presence or absence of Ca2+, phospholipid and Factor V. In contrast, heparin decasaccharide (Mr 3000) and pentasaccharide (Mr 1500) fragments were unable to overcome the protective effect of Ca2+/phospholipid/Factor V; in the presence of these components their catalytic efficiencies were 16-fold and 40-fold less respectively than that of unfractionated heparin. A heparin 20-22-saccharide fragment (Mr approx. 6000) gave similar inactivation rates in the presence and in the absence of Ca2+/phospholipid/Factor V. Human and bovine Factor Xa gave similar results. These results indicate that in the presence of Ca2+/phospholipid/Factor V optimum inhibition of Factor Xa requires a saccharide sequence of heparin additional to that involved in binding to antithrombin III. The use of free enzyme for the assessment of anti-(Factor Xa) activity of low-Mr heparin fractions could give misleading results.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

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.

Covalent Complexes Between Low Molecular Weight Heparin Fragments and Antithrombin III – Inhibition Kinetics and Turnover Parameters

1983 ◽  
Vol 49 (02) ◽  
pp. 109-115 ◽  
Author(s):  
M Hoylaerts ◽  
E Holmer ◽  
M de Mol ◽  
D Collen
Keyword(s):  
Molecular Weight ◽  
Half Life ◽  
Low Molecular Weight Heparin ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Life Time ◽  
Low Molecular Weight ◽  
High Affinity ◽  
Plasma Half Life ◽  
Covalent Complex

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).

scholarly journals Thrombin Metz: characterization of the dysfunctional thrombin derived from a variant of human prothrombin

Blood ◽  
1984 ◽  
Vol 63 (4) ◽  
pp. 927-934
Author(s):  
MJ Rabiet ◽  
M Jandrot-Perrus ◽  
JP Boissel ◽  
J Elion ◽  
F Josso
Keyword(s):  
High Performance ◽  
Fluorescence Enhancement ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Competitive Inhibitor ◽  
Amidolytic Activity ◽  
Direct Inhibition ◽  
High Affinity ◽  
Factor Va

Thrombin Metz and normal thrombin, resulting from activation of the respective prothrombins by factor Xa in the presence of calcium, phospholipid, and factor Va, were purified by chromatography on sulfopropyl Sephadex. By physicochemical criteria, thrombin Metz is identical to normal thrombin. Its functional properties were investigated in some reactions in which thrombin is classically involved. Thrombin Metz exhibits less than 4% of fibrinogen clotting activity. Both Km and Kcat, determined on S2238, are abnormal. Titration with the high-affinity competitive inhibitor of thrombin, DAPA, shows that fluorescence enhancement of the probe is only 34% in binding to thrombin Metz when compared to that observed in binding to normal thrombin. High-performance liquid chromatography has been used to measure the simultaneous rate of release of fibrinopeptides A and B. A decreased release rate for both fibrinopeptides, more marked for fibrinopeptide B, results in a slow fibrin polymerization, as followed by absorbance at 450 nm. Thrombin Metz is less than 5% as effective as normal thrombin in inducing platelet aggregation. Interaction with antithrombin III is slower than normal when followed by SDS gel electrophoresis and inhibition of the amidolytic activity of thrombin on S2238. This abnormality is not observed in the presence of heparin. However, thrombin Metz binds less tightly to a heparin-Sepharose column, and the direct inhibition of heparin on its activity on S2238 is weaker. From these results, we can predict that the defect in thrombin Metz affects the catalytic site or its vicinity and, jointly or consequently, the region of interaction of thrombin with antithrombin III and heparin.

The Heparin Binding Site Of Antithrombin: Identification Of A Critical Tryptophan Residue Within The Amino Acid Sequence

1981 ◽  
Author(s):  
M Blackburn
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Antithrombin Iii ◽  
Factor Xa ◽  
Tryptophan Fluorescence ◽  
Tryptophan Residue ◽  
Affinity Column ◽  
Heparin Binding ◽  
High Affinity ◽  
Heparin Binding Site

Chemical modification of antithrombin III with the tryptophan reagent, dimethyl (2-hydroxy-5-nitrobenzyl) sulfonium bromide, results in the incorporation of one hydroxynitrobenzyl (HNB) moiety per molecule of antithrombin III. Heparin protects against tryptophan modification, particularly at low reagent concentrations. Unlike native antithrombin, which has high affinity for heparin, HNB-anti- thrombin does not bind to a heparin-agarose affinity column. Furthermore, the heparin-induced increase in tryptophan fluorescence, obtained with native antithrombin, is not observed with the singly modified inhibitor. HNB-anti- thrombin does not exhibit heparin-promoted rate enhancement in the inactivation of thrombin and Factor Xa. However, in the absence of heparin, HNB-antithrombin and native antithrombin possess progressive antithrombin activity, inactivating these proteases at identical rates. These results indicate that the integrity of a specific tryptophan residue is required for the binding of heparin to antithrombin III. Chemical and enzymatic cleavage techniques have been used to isolate peptides containing this tryptophan from both HNB-labeled and native antithrombin and to identify this critical tryptophan residue within the amino acid sequence of the antithrombin molecule.

Structure of the Antithrombin III-Binding site in Heparin

1979 ◽  
Author(s):  
U. Lindahl ◽  
G. Bäckström ◽  
N. Höök ◽  
J. Riesenfeld ◽  
L. Thunberg ◽  
...  
Keyword(s):  
Antithrombin Iii ◽  
Anticoagulant Activity ◽  
Periodate Oxidation ◽  
Variable Structure ◽  
Variable Regions ◽  
High Affinity ◽  
Swedish Medical ◽  
A Minor ◽  
Binding Sequence ◽  
Partial Chemical

Fragments with high affinity for antithrombin III (AT), composed of 12 to 16 monosaccharide units, were isolated from heparin after partial chemical or enzymatic depolymerization of the polysaccharide. Analysis of such fragments based on identification ot deamination products suggested that nonsulfated L-iduronic acid (a minor constituent) is essential for the anticoagulant activity of heparin. The location of this unit in the AT-binding sequence was determined by periodate oxidation. Furthermore, an N-sulfate group essential for activity was located by structural analysis of partially N-desulfated fragments retaining high affinity for AT. It is proposed that the AT-hinding sequence in heparin has a variable structure containing certain nonvanable regions. A tentative structure for this sequence is presented, with indication of identified constant and variable regions.(Supported by grant No. 2309 from the Swedish Medical Research Council).

ANTITHROMBIN III BINDING TO IMMOBILIZED HEPARIN FRAGMENTS AND ITS RELATION TO F XA INHIBITION

1987 ◽  
Author(s):  
K Kodama ◽  
O Larm ◽  
P Olsson ◽  
B Pasehe ◽  
J Risenfeldt ◽  
...  
Keyword(s):  
Binding Sites ◽  
Antithrombin Iii ◽  
Cellular Membrane ◽  
Tris Buffer ◽  
Buffer Solution ◽  
Thrombin Inhibition ◽  
High Affinity ◽  
Inhibitory Capacity ◽  
Nacl Concentration ◽  
Binding Sequence

Covalent end-point attachment of heparin fragments (8 000 daltons) to artitifical materials results as published before in a highly thromboresistant surface. Approximately one out of six bonded fragments carry the antithrombin III (AT) binding sequence. i.e. the high affinity site. With regard to thrombin inhibition the heparin surface resembles the endothelium. The present work deals with the uptake on the immobilized heparin and its significance for F Xa inhibition. The uptake of AT was studied at 0.15 M and 0.35 M NaCl concentration (TRIS buffer, pH 7.4) respectively and determined as disappearance of AT activity in the exposed solutions. Large amounts were adsorbed at 0.15 M and the uptake was both concentration and time dependent. At 0.35 M the uptake was the same at all the tested AT concentrations: 5 pico-moles/square cm. It was deduced that mainly high affinity sites had taken up AT at 0.35 M and that both high and low affinity sites had taken up AT at 0.15 M.The non-AT-adsorbed heparin surface did not induce inhibition of F Xa (in TRIS buffer solution) after exposure. The surface AT-adsorbed at 0.15 M induced F Xa inhibition with the same rate in several consecutive exposed aliquots. The surface AT-adsorbed at 0.35 M had a lower inhibitory capacity and only the first F Xa aliquot was inhibited at the same rate as on the surface AT-adsorbed at 0.15 M. The inhibition rate for a second aliquot was slowlier due to the facts that AT had been consumed and that the density of AT on high affinity sites had decreased. It is concluded that AT on high affinity sites determines the rate at which F Xa is inhibited whereas the amount of AT on low affinity sites determines the inhibitory capacity by continously providing the high affinity sites with AT. The migration of AT must take place horizontally in the 100-200 A thick surface layer and may mimic events happening on a cellular membrane with binding sites of different classes for a substance.

scholarly journals Effect of oversulphated chondroitin and dermatan sulphate upon thrombin and factor Xa inactivation by antithrombin III or heparin cofactor II

1988 ◽  
Vol 254 (2) ◽  
pp. 547-551 ◽  
Author(s):  
M F Scully ◽  
V Ellis ◽  
N Seno ◽  
V V Kakkar
Keyword(s):  
Antithrombin Iii ◽  
Chondroitin Sulphate ◽  
Factor Xa ◽  
Dermatan Sulphate ◽  
Physiological Control ◽  
Heparin Cofactor Ii ◽  
High Affinity ◽  
Human Thrombin ◽  
Sulphated Glycosaminoglycans ◽  
Inhibition Of Thrombin

The kinetics of inhibition of human thrombin and Factor Xa by antithrombin III or heparin cofactor II were examined under pseudo-first-order conditions as a function of the concentration of naturally occurring oversulphated chondroitin and dermatan sulphates. The sulphated glycosaminoglycans (GAGs) studied were chondroitin sulphate D (CSD) (GlcA-2-SO4-GalNAc-6-SO4), chondroitin sulphate K (CSK) (GlcA-3-SO4-GalNAc-4-SO4), chondroitin sulphate H (CSH) (IdA-GalNAc-4,6-diSO4) and polysulphated dermatan sulphate (DPS) (IdA-2-SO4 or -3-SO4-GalNAc-4,6-diSO4). The data for the antithrombin III inhibition of thrombin showed a low degree of maximal potentiation of this interaction (congruent to 10-fold), which would appear to be characteristic of GAGs devoid of the high-affinity antithrombin III binding site. In contrast there was a greater potentiation of the inhibition of thrombin by heparin cofactor II with DPS showing an activity comparable to heparin in this interaction at a concentration two orders of magnitude lower than dermatan sulphate. DPS potentiated antithrombin III-Factor Xa interaction by 1200-fold, similar to that shown by high-affinity heparin of 6 kDa. The antithrombin III-Factor Xa interaction was potentiated by all other GAGs studied to a degree similar to that of heparin pentasaccharide with high affinity for antithrombin III. The findings suggest more stringent structural requirements for GAG stimulation of antithrombin-thrombin interaction than for antithrombin-Factor Xa or heparin cofactor-thrombin interaction, which may also be of significance in physiological control of haemostasis.

scholarly journals Binding of platelet factor 4 to heparin oligosaccharides

1983 ◽  
Vol 209 (2) ◽  
pp. 455-460 ◽  
Author(s):  
J Denton ◽  
D A Lane ◽  
L Thunberg ◽  
A M Slater ◽  
U Lindahl
Keyword(s):  
Specific Activity ◽  
Gel Filtration ◽  
Factor Xa ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Physiological Conditions ◽  
Heparin Fractions ◽  
Specific Activities ◽  
Binding Sequence ◽  
Heparin Oligosaccharides

Heparin fractions of differing Mr (7800-18 800) prepared from commercial heparin by gel filtration and affinity chromatography on immobilized anti-thrombin III had specific activities when determined by anti-Factor Xa and anti-thrombin assays that ranged from 228 to 448 units/mg. The anti-Factor Xa activity of these fractions could be readily and totally neutralized by increasing concentrations of platelet factor 4 (PF4). That these fractions bound to immobilized PF4 was indicated by the complete binding under near physiological conditions of 3H-labelled unfractionated commercial heparin. An anti-thrombin III-binding oligosaccharide preparation (containing predominantly eight to ten saccharide units), prepared by degradation of heparin with HNO2 had high (800 units/mg) anti-Factor Xa, but negligible anti-thrombin, specific activity. The anti-Factor Xa activity of this material could not be readily neutralized by PF4, and the 3H-labelled oligosaccharides did not completely bind to immobilized PF4. A heterogeneous anti-thrombin III-binding preparation containing upwards of 16 saccharides had anti-thrombin specific activity of just less than one-half the anti-Factor Xa specific activity. This material was completely bound to immobilized PF4 and was eluted with similar concentrations of NaCl to those that were required to elute unfractionated heparins from these columns. Furthermore, increasing concentrations of PF4 neutralized the anti-Factor Xa activity of this material in a manner similar to that of unfractionated heparin. It is concluded that heparin oligosaccharides require saccharide units in addition to the anti-thrombin III-binding sequence in order to fully interact with PF4.

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