scholarly journals The synthesis of arginylfluoroalkanes, their inhibition of trypsin and blood-coagulation serine proteinases and their anticoagulant activity

1990 ◽  
Vol 265 (2) ◽  
pp. 539-545 ◽  
Author(s):  
T Ueda ◽  
C M Kam ◽  
J C Powers

Seven arginylfluoroalkanes (‘arginine fluoroalkyl ketones’) were synthesized by using a modified Dakin-West procedure. The structure of benzoyl-Arg-CF2CF3 was analysed by 19F-n.m.r. spectroscopy and m.s. and the compound was shown to exist primarily as a hydrate or cyclic carbinolamine. Arginylfluoroalkanes are good inhibitors of blood-coagulation serine proteinases and were found to be slow-binding inhibitors for bovine trypsin with Ki values of 0.2-56 microM. Benzoyl-Arg-CF2CF3 was the best inhibitor for bovine thrombin and human Factor XIa, and inhibited thrombin and Factor XIa competitively with Ki values of 13 microM and 62 microM respectively. The best inhibitor for pig pancreatic kallikrein was p-toluoyl-Arg-CF3, with a Ki value of 35 microM. Benzoyl-Arg-CF3 and benzoyl-Arg-CF2CF3 inhibited human plasma kallikrein competitively, with Ki values of 50 microM. None of the seven arginylfluoroalkanes was a good inhibitor of human factor Xa or of Factor XIIa. The arginylfluoroalkanes were tested in the prothrombin time (PT) and activated partial thromboplastin time (APTT) coagulant assays. Two fluoroketones, benzoyl-Arg-CF2CF3 and 1-naphthoyl-Arg-CF3, had significant anticoagulant activity. Benzoyl-Arg-CF2CF3 was found to prolong the PT 1.8-fold at 120 microM and to prolong the APTT 2.4-fold at 90 microM, whereas 1-naphthoyl-Arg-CF3 only prolonged the APTT 1.7-fold at 100 microM.

2021 ◽  
Vol 14 (9) ◽  
pp. 886
Author(s):  
Srabani Kar ◽  
Page Bankston ◽  
Daniel K. Afosah ◽  
Rami A. Al-Horani

The anticoagulant activity of lignosulfonic acid sodium (LSAS), a non-saccharide heparin mimetic, was investigated in this study. LSAS is a relatively safe industrial byproduct with similar polyanionic characteristics to that of heparin. Human plasma clotting assays, fibrin polymerization testing, and enzyme inhibition assays were exploited to investigate the anticoagulant activity of LSAS. In normal human plasma, LSAS selectively doubled the activated partial thromboplastin time (APTT) at ~308 µg/mL. Equally, LSAS doubled APTT at ~275 µg/mL in antithrombin-deficient plasma. Yet, LSAS doubled APTT at a higher concentration of 429 µg/mL using factor XI-deficient plasma. LSAS did not affect FXIIIa-mediated fibrin polymerization at 1000 µg/mL. Enzyme assays revealed that LSAS inhibits factor XIa (FXIa) with an IC50 value of ~8 μg/mL. LSAS did not inhibit thrombin, factor IXa, factor Xa, factor XIIIa, chymotrypsin, or trypsin at the highest concentrations tested and demonstrated significant selectivity against factor XIIa and plasmin. In Michaelis–Menten kinetics, LSAS decreased the VMAX of FXIa hydrolysis of a tripeptide chromogenic substrate without significantly changing its KM indicating an allosteric inhibition mechanism. The inhibitor also disrupted the generation of FXIa–antithrombin complex, inhibited factor XIIa-mediated and thrombin-mediated activation of the zymogen factor XI to FXIa, and competed with heparin for binding to FXIa. Its action appears to be reversed by protamine sulfate. Structure–activity relationship studies demonstrated the advantageous selectivity and allosteric behavior of LSAS over the acetylated and desulfonated derivatives of LSAS. LSAS is a sulfonated heparin mimetic that demonstrates significant anticoagulant activity in human plasma. Overall, it appears that LSAS is a potent, selective, and allosteric inhibitor of FXIa with significant anticoagulant activity in human plasma. Altogether, this study introduces LSAS as a promising lead for further development as an anticoagulant.


1998 ◽  
Vol 79 (02) ◽  
pp. 296-301 ◽  
Author(s):  
Ron Blezer ◽  
George Willems ◽  
Patrick Cahalan ◽  
Theo Lindhout

SummaryWe have made use of a novel flow reactor to study the initiation and propagation of the ex vivo blood coagulation processes at artificial surfaces. The flow reactor consisted of a primary glass or polymer capillary that is connected to a secondary glass capillary, which inner wall was coated with a phospholipid bilayer of 25 mol% dioleoylphosphatidylserine/75 mol% dioleoylphosphatidylcholine (DOPS/DOPC). Citrated platelet free plasma and a CaCl2 solution were delivered by syringe pumps and mixed just before the entrance of the flow reactor. The outflowing plasma was assayed for factor XIa, factor IXa, factor Xa and thrombin activity. Perfusion of recalcified plasma through a bare glass capillary resulted in a transient generation of fluid phase factor XIa. In contrast, factor IXa production increased slowly to attain a stable steady-state level. We established that surface-bound factor XIa was responsible for a continuous production of factor IXa. Factor IXa-induced generation of factor Xa and thrombin was only observed when contact activated plasma was subsequently perfused through a DOPS/DOPC-coated capillary, showing that propagation of the factor IXa trigger requires a procoagulant, phosphatidylserine-containing, phospholipid membrane. The negatively charged inner surface of a heparin-coated polyurethane capillary, generated like the glass capillary significant amounts of factor XIa and factor IXa when perfused with recalcified plasma. No differences were found between unfractionated heparin and heparin devoid of anticoagulant activity. Thus, it is concluded that contact activation and factor IXa generation in flowing plasma is not inhibited by immobilised anticoagulant active heparin. Consequently, factor IXa-dependent thrombin generation at a downstream located phospholipid membrane was similar, regardless the specific anticoagulant activity of immobilised heparin.


2005 ◽  
Vol 94 (11) ◽  
pp. 1084-1093 ◽  
Author(s):  
Ingo Banke ◽  
Matthias Arlt ◽  
Markus Mueller ◽  
Stefan Sperl ◽  
Axel Stemberger ◽  
...  

SummaryClinical and experimental evidence suggests that the blood coagulation system is involved in the dissemination of malignant tumors. Consequently, anticoagulant agents have been tested as metastasis suppressors in experimental models. Recently, we have found a close correlation between factor Xa (FXa)-specificity of a series of synthetic serine protease inhibitors and their anti-metastatic potential in a murineT-cell lymphoma metastasis model. Interference of such inhibitors with blood-coagulation may represent a major experimental and clinical obstacle. Here, we test anti-metastatic effects of a recently developed, highly specific 3-amidinophenylalanine-type FXa inhibitor, WX-FX4, with weaker anticoagulant activity when compared to well-established FXa inhibitors, such as DX-9065a, as measured by the activated partial thromboplastin time, prothrombin time, prothrombinase complex activity, and coagulation time. Treatment of mice with WX-FX4 (1.5 mg/kg twice daily) led to significant reduction of experimental liver metastasis of a syngeneic T-cell lymphoma in DBA/2 mice (> 90%), and of experimental lung metastasis of a human fibrosarcoma in CD1 nu/nu mice (> 60%). Due to its relatively low anticoagulant activity, daily treatment over 100 days was possible, leading to significant survival benefits without inducing bleeding anomalities. FXa-inhibitors with highly efficient anti-metastatic potential without coagulationrelated side effects may represent important new tools as anticancer agents.


1983 ◽  
Vol 215 (2) ◽  
pp. 287-294 ◽  
Author(s):  
R R Cook ◽  
J C Powers

Benzyl p-guanidinothiobenzoate hydrochloride was synthesized and demonstrated to be useful for active-site titration of bovine trypsin, bovine thrombin, human lung tryptase, bovine activated protein C, human Factor XIIa fragment and bovine Factor Xa beta. The titration is based on rapid formation of a stable acyl-enzyme with a stoichiometric release of benzyl thiol. Thiol production is measured quantitatively by including 4,4′-dithiodipyridine in the reaction mixture and measuring the increase in absorbance at 324 nm. Ellman's reagent has also been successfully employed, allowing measurement at 410 nm. Unlike p-nitrophenyl p'-guanidinobenzoate, the thioester titrant reacts slowly with chymotrypsin A alpha thus eliminating interference by this enzyme in most titrations. Advantages of this reagent as a titrant include: flexibility in detection of the released thiol, selectivity between trypsin and chymotrypsin-like enzymes, minimal pH-dependence of the epsilon of the absorbing species, relative stability of the reagent under titration conditions, and high epsilon at pH 7.2 with either 4,4′-dithiodipyridine or Ellman's reagent. The reagent should prove useful as an alternative to p-nitrophenyl p'-guanidinobenzoate hydrochloride for the determination of active-site concentrations of the enzymes employed, as well as of other related enzymes.


1994 ◽  
Vol 72 (03) ◽  
pp. 397-402 ◽  
Author(s):  
Peter A Kr von dem Borne ◽  
Stefan J Koppelman ◽  
Bonno N Bouma ◽  
Joost C M Meijers

SummaryA deficiency of one of the proteins of the contact system of blood coagulation does not result in a bleeding disorder. For this reason activation of blood coagulation via this system is believed to be an in vitro artefact. However, patients deficient in factor XI do suffer from variable bleeding abnormalities. Recently, an alternative pathway for factor XI activation has been described. Factor XI was found to be activated by thrombin in the presence of dextran sulfate as a surface. However, high molecular weight kininogen (HK), to which factor XI is bound in plasma, and fibrinogen were shown to block this activation suggesting it to be an in vitro phenomenon. We investigated the thrombin-mediated factor XI activation using an amplified detection system consisting of factors IX, VIII and X, which was shown to be very sensitive for factor XIa activity. This assay is approximately 4 to 5 orders of magnitude more sensitive than the normal factor XIa activity assay using a chromogenic substrate. With this assay we found that factor XI activation by thrombin could take place in the absence of dextran sulfate. The initial activation rate was approximately 0.3 pM/min (using 25 nM factor XI and 10 nM thrombin). The presence of dextran sulfate enhanced this rate about 8500-fold. A very rapid and complete factor X activation was observed in the presence of dextran sulfate. Although only minute amounts of factor XIa were formed in the absence of dextran sulfate, significant activation of factor X was detected in the amplification assay within a few minutes. HK inhibited the activation of factor XI by thrombin strongly in the presence, yet only slightly in the absence of dextran sulfate (26 and 1.2 times, respectively). Despite the strong inhibition of HK on the activation of factor XI by thrombin in the presence of dextran sulfate, HK had only a minor effect on the factor Xa generation.We conclude that activation of factor XI by thrombin can take place regardless of the presence of a surface or HK. This activation might therefore be physiologically relevant. The inhibitory effect of HK on the thrombin-mediated factor XI activation is largely dextran sulfate dependent. Due to the amplification in the intrinsic system, trace amounts of factor XIa might generate physiological sufficient amounts of factor Xa for an adequate haemostatic response.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1889 ◽  
Author(s):  
Nadezhda Novichikhina ◽  
Ivan Ilin ◽  
Anna Tashchilova ◽  
Alexey Sulimov ◽  
Danil Kutov ◽  
...  

Coagulation factor Xa and factor XIa are proven to be convenient and crucial protein targets for treatment for thrombotic disorders and thereby their inhibitors can serve as effective anticoagulant drugs. In the present work, we focused on the structure–activity relationships of derivatives of pyrrolo[3,2,1-ij]quinolin-2(1H)-one and an evaluation of their activity against factor Xa and factor XIa. For this, docking-guided synthesis of nine compounds based on pyrrolo[3,2,1-ij]quinolin-2(1H)-one was carried out. For the synthesis of new hybrid hydropyrrolo[3,2,1-ij]quinolin-2(1H)-one derivatives, we used convenient structural modification of both the tetrahydro- and dihydroquinoline moiety by varying the substituents at the C6,8,9 positions. In vitro testing revealed that four derivatives were able to inhibit both coagulation factors and three compounds were selective factor XIa inhibitors. An IC50 value of 3.68 μM for was found for the best factor Xa inhibitor and 2 μM for the best factor XIa inhibitor.


Author(s):  
М.С. Успенская ◽  
М.Г. Ляпина ◽  
М.Д. Калугина

Введение. Актуальность темы исследования обусловлена проблемой борьбы с тромбозами и тромбоэмболиями безопасными для организма методами. Во многих растениях обнаружены антикоагулянты разной природы (гепариноподобные, пептиды). Цель исследования - изучение возможности проявления синергических эффектов на антикоагулянтную и фибринолитическую активность крови и процессы полимеризации фибрина экстракта из корней пиона «Иван Горожанкин» в сравнительном аспекте с действием экстракта из корней пиона «молочноцветковый». Методика. Объектом исследования служили корни пионов «Иван Горожанкин» и «молочноцветковый», произрастающих в Ботаническом саду МГУ. Пион «Иван Горожанкин» был создан скрещиванием пиона «молочноцветкового» и «лекарственного» Разработаны методы получения экстрактов из корней различных пионов. При различных разведениях экстрактов (0.1, 1, 5%) определены антикоагулянтная активность по тестам, характеризующим внутренний, внешний и общий пути свертывания крови, а также степень полимеризации фибрина плазмы крови крыс. Для сравнения был использован стандартный препарат низкомолекулярного гепарина (LMWH) животного происхождения фирмы «Celsus» (США). Проведены выделение и очистка активного начала (гепариноидов) из сухих препаратов и измерены их активности. Pезультаты. Показано, что экстракты из обоих препаратов пионов обладали антикоагулянтной и суммарной фибринолитической активностью на нестабилизированном фибрине, но в разной степени. В экстрактах из корней пиона «Иван Горожанкин» отмечались преимущественные синергические эффекты, а именно превышение антикоагулянтной активности на 20-30%, суммарной фибринолитической - на 18% по сравнению с таковыми, отмечаемыми в экстрактах из корней пиона «молочноцветковый». Подобные результаты выявлены и при изучении степени полимеризации фибрина под влиянием очищенных препаратов из пионов. Рассмотрены возможные механизмы активирующего действия экстракта из пиона «Иван Горожанкин» на антикоагулянтные свойства плазмы, суммарную фибринолитическую активность и степень полимеризации фибрина. Это связано с блокадой активности тромбина и факторов внутреннего механизма свертывания крови. При этом антикоагулянтный эффект от применения экстракта из пиона «Иван Горожанкин» по тесту APTT (activated partial thromboplastin time) превышал на 20-30% ту же активность, выявленную у пиона «молочноцветковый», которая соответствовала антикоагулянтной активности препарата сравнения LMWH. В экстракте из пиона «Иван Горожанкин» впервые обнаружено наличие антикоагулянтного гепариноподобного вещества. Заключение. Впервые установлена способность экстракта из корней пиона «Иван Горожанкин» проявлять синергические антикоагулянтные и фибриндеполимеризационные эффекты, превышающие таковые у экстракта из пиона «молочноветковый». На основе полученных данных возникает необходимость исследования пиона «Иван Горожанкин» в качестве антитромботического, а возможно, и антиатеросклеротического агента. Introduction. The research topic is relevant due to the problem of safely combating thrombosis and thromboembolism. Anticoagulants of various kinds, e.g., heparin-like and peptides, have been found in many plants. Aim. To investigate the possibility of synergistic effects on the blood anticoagulant and fibrinolytic activity and on processes of fibrin polymerization by an extract from the roots of the «Ivan Gorozhankin» peony compared with the root extract from «Paeonia lactiflora». Methods. The focus of the study was the roots of the “Ivan Gorozhankin” peony and the Paeonia lactiflora growing in the Botanical Garden of the Moscow State University. The “Ivan Gorozhankin” peony was created by crossing P. lactiflora and the “medicinal” peony. Methods for obtaining extracts from the roots of various peonies have been developed. In 1%, 3%, and 5% dilutions of the extracts, the anticoagulant activity was determined according to tests characterizing the internal, external and general blood coagulation pathways, as well as by the degree of polymerization of rat blood plasma fibrin. For comparison, we used a standard preparation of low molecular weight heparin (LMWH) of animal origin (Celsus, USA). Isolation and purification of the active substances, heparinoids, were isolated from dry preparations and purified, and their activities were measured. Results. Extracts from both peony preparations had anticoagulant and total fibrinolytic activity on unstabilized fibrin, but to different extents. In the extracts from the roots of the “Ivan Gorozhankin” peony, preferential synergistic effects were noted, namely, the anticoagulant activity was higher by 20-30%, and the total fibrinolytic activity was higher by 18% compared to those of extracts from Paeonia lactiflora roots. Similar results were obtained when studying the degree of fibrin polymerization as influenced by purified peony preparations. Possible mechanisms of the activating action of the «Ivan Gorozhankin» peony extract on the anticoagulant properties of plasma, the total fibrinolytic activity, and the degree of fibrin polymerization are considered. This action is due to the inhibition of thrombin activity and factors of the internal mechanism of blood coagulation. According to the activated partial thromboplastin time (APTT) test, the anticoagulant effect of extracts from the «Ivan Gorozhankin» peony exceeded by 20-30% the activity of Paeonia lactiflora extract, which corresponded to the anticoagulant activity of the LMWH comparator drug. Using the described biochemical methods, the presence of an anticoagulant heparin-like substance in an extract from the peony «Ivan Gorozhankin» has been discovered. Conclusion. For the first time, the ability of an extract from the roots of the «Ivan Gorozhankin» peony to exhibit synergistic anticoagulant and fibrin-depolymerization effects was demonstrated. These effects exceeded those of the Paeonia lactiflora extract. Based on these data, it appears necessary to study the «Ivan Gorozhankin» peony as an antithrombotic, and possibly as an anti-atherosclerotic agent.


1998 ◽  
Vol 79 (03) ◽  
pp. 543-548 ◽  
Author(s):  
Yumiko Sakai ◽  
Nami Hisamichi ◽  
Makoto Kayama ◽  
Yuji Mano ◽  
Kazuo Sato ◽  
...  

SummaryYM-60828 was found to potently inhibit human factor Xa following oral administration. YM-60828 showed high affinity for factor Xa (Ki = 1.3 μM), but did not affect thrombin (Ki > 100 μM). YM-60828 doubled factor Xa clotting time, prothrombin time (PT) and activated partial thromboplastin time (APTT) at 0.10, 0.21, 0.24 μM, respectively. Importantly, it did not prolong thrombin time at 100 μM. YM-60828 also inhibited factor Xa in the prothrombinase complex with an IC50 value of 7.7 nM. In addition to its anticoagulant activity, YM-60828 inhibited platelet aggregation induced by various agonists (IC50 = 3 to 23 μM). Squirrel monkeys were used to study the ex vivo anticoagulant activity and pharmacokinetic properties of YM-60828. One hour after oral administration at 3 mg/kg, YM-60828 strongly prolonged PT and APTT by 4.8- and 1.9-fold, respectively, and plasma concentration reached 788 ± 167 ng/ml. Bioavailability was calculated to be 20.3%. These results strongly suggest that YM-60828 will be a valuable orally active and potent anticoagulant agent showing potential antithrombotic activity.


1979 ◽  
Author(s):  
R. R. Tidwell ◽  
J. D. Geratz

A series of ten newly synthesized amidine-substituted heterocycles were examined for their inhibitory effect against human and bovine thrombin, human factor Xa and plasmin, and bovine trypsin. Inhibition was competitive and reversible in all cases and the Kj values were taken to reflect binding conditions in the specificity pocket A remarkable inhibitor of the three clotting enzymes was found in 5-amidlnoindole. Compared to the standard inhibitor benzamidine, it proved to be thirty to forty times more effective against bovine and human thrombin, and factor-Xa. However b-amidinomdole proved to be the most potent inhibitor of plasmin and trypsin‘in order to explain the considerable activity of the indole derivatives, hydrophobic interactions, hydrogen bonding and charge transfer complex formation are considered Finallythe binding strength for thrombin as well as for trypsin was significantly reduced below pH 7.0. The loss in affinity may have resulted from protonation of the ammo acid triad of the catalytic site of the enzymes and consequent adverse conformational changes. This study was supported by U. S. Public Service Grants AM 10746 and HL 21540.


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