The role of surface charge on the accelerating action of heparin on the antithrombin III-inhibited activity of alpha-thrombin.

Heuck, C C; Schiele, Ulrike; Horn, D.; Fronda, D; Ritz, E

doi:10.1016/s0021-9258(18)89113-x

Cited by 53 publications

(14 citation statements)

References 31 publications

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“…52,53 Electrophoretic transport is particularly attractive as many of the most commonly used drug molecules and therapeutic agents are electrically charged while solvated in PBS or in aqueous solutions at pH 7. [54][55][56] Drugs that could benefit from electrophoretic delivery techniques include chemotherapeutic agents, 41 anticoagulants, 50 and analgesics. 34 The operational range of release rates for the nDS is set by the mechanical dimensions of the fluidic network, the highest voltage possible without significant electrolysis, and the electrophoretic mobility of the molecule.…”

Section: Discussionmentioning

confidence: 99%

“…A titration value indicating the maximum theoretical charge of À11 for BSA is available; however, shielding by the solvent plays a crucial role on the effective charge which produces the electromotive force in the presence of an electric field. 56 Estimated ratios of 7 to 10 FITC per BSA, with a theoretical charge of À1 for each FITC, have been reported in the literature. 66 Therefore the total charge on the molecule could theoretically approach À18 in pH 6.8 (7 Â À1 + À11).…”

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confidence: 95%

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A low-voltage electrokinetic nanochannel drug delivery system

et al. 2011

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Recent work has elucidated the potential of important new therapeutic paradigms, including metronomic delivery and chronotherapy, in which the precise timing and location of therapeutic administration has a significant impact on efficacy and toxicity. New drug delivery architectures are needed to not only release drug continuously at precise rates, but also synchronize their release with circadian cycles. We present an actively controlled nanofluidic membrane that exploits electrophoresis to control the magnitude, duration, and timing of drug release. The membrane, produced using high precision silicon fabrication techniques, has platinum electrodes integrated at the inlet and outlet that allow both amplification and reversal of analyte delivery with low applied voltage (at or below 2 VDC). Device operation was demonstrated with solutions of both fluorescein isothiocyanate conjugated bovine serum albumin and lysozyme using fluorescence spectroscopy, fluorescence microscopy, and a lysozyme specific bio-assay and has been characterized for long-term molecular release and release reversibility. Through a combination of theoretical and experimental analysis, the relative contributions of electrophoresis and electroosmosis have been investigated. The membrane's clinically relevant electrophoretic release rate at 2 VDC exceeds the passive release by nearly one order of magnitude, demonstrating the potential to realize the therapeutic paradigm goal.

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Section: Discussionmentioning

confidence: 99%

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confidence: 95%

A low-voltage electrokinetic nanochannel drug delivery system

et al. 2011

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“…Heparin has the highest negative charge density of any known biological molecule. 38 Heparan sulfate is structurally very similar to heparin, but its disaccharide units are organized into distinct sulfated and nonsulfated domains. 45 Hyaluronic Acid and Chondroitin Sulfate.…”

Section: ■ Discussionmentioning

confidence: 99%

“…47 Chondroitin sulfate is the main GAG in human plasma. 38 Its plasma concentration in healthy humans ranges from 3.69 to 6.65 μg/mL and in patients with arthrosclerosis from 4.0 to 8.56 μg/mL. 48 It is also present at a concentration of 0.55 mg/mL in the synovium and ∼0.04 mg/ mL in synovial fluid.…”

Section: ■ Discussionmentioning

confidence: 99%

Stability of Dendriplexes Formed by Anti-HIV Genetic Material and Poly(propylene imine) Dendrimers in the Presence of Glucosaminoglycans

et al. 2012

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There are several barriers to the application of dendriplexes formed by poly(propylene imine) dendrimers and genetic material for gene therapy. One limitation is their interaction with extracellular matrix components such as glucosaminoglycans. These can displace the genetic material from the dendriplexes, affecting their transfection activity. In this study, we analyzed the interaction between dendriplexes and the four main glucosaminoglycans (heparin, heparan sulfate, chondroitin sulfate, and hyaluronic acid) by fluorescence polarization and gel electrophoresis. Dendriplexes were formed by combining three anti-HIV antisense oligodeoxynucleotides with three poly(propylene imine) dendrimers of the fourth generation: unmodified and partially modified with maltose and maltotriose (open shell glycodendrimers). The data showed that the effect of glucosaminoglycans on dendriplexes depends on the glucosaminoglycan type and the oligosaccharide serving as the surface group of the dendrimer. Heparin at physiological concentrations destroys dendriplexes formed by open shell glycodendrimers, but dendriplexes based on unmodified poly(propylene imine) dendrimers are stable in its presence. The other glucosaminoglycans at physiological concentrations cannot destroy dendriplexes formed by any of the dendrimers studied.

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“…appear to be important in the enhancement of activation of protein C by the chondroitin sulphate moiety of thrombomodulin [40]. Unlike antithrombin III, the binding of thrombin to heparin is not dependent upon sequence-specific sites within heparin but occurs non-specifically to the region via electrostatic interaction [41]. This electrostatic association has been estimated from binding studies to be due to five or six anionic residues [42] which would be contained within a two-disaccharide length of the polysaccharide chain.…”

Section: Discussionmentioning

confidence: 99%

Heparin enhances the catalytic activity of des-ETW-thrombin

Goodwin

Deadman

Bonniec

et al. 1996

Biochemical Journal

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The thrombin mutant, des-ETW-thrombin, lacking Glu(146), Thr(147), and Trp(148) within a unique insertion loop located at the extreme end of the primary specificity pocket, has been shown previously to exhibit reduced catalytic activity with respect to macromolecular and synthetic thrombin substrates and reduced or enhanced susceptibility to inhibition. Investigation of the hydrolysis of peptidyl p-nitroanilide substrates by des-ETW-thrombin showed increased activity in the presence of heparin and other sulphated glycosaminoglycans. No effect was observed upon the activity of wild-type thrombin. Heparin was found to decrease the K(m) for cleavage of four thrombin-specific substrates by des-ETW-thrombin by 3-4-fold. Similarly, pentosan polysulphate (PPS) decreased the K(m) with these substrates by 8-10-fold. Heparin also increased the rate of inhibition of des-ETW-thrombin by antithrombin III and D-phenylalanyl-prolyl-arginylchloromethane (PPACK). The inhibition of des-ETW-thrombin by a number of thrombin-specific peptide boronic acids also showed significant reduction in the final K(i) in the presence of heparin, due to reduction in the off-rate. A peptide analogue of a sequence of hirudin which binds thrombin tightly to exosite I (fibrinogen recognition site) potentiated the activity of des-ETW-thrombin against peptide p-nitroanilide substrates in a manner similar to heparin. The K(i) for the inhibition of des-ETW-thrombin by p-aminobenzamidine was decreased by these ligands from 9.7 mM to 7.5 mM, 5.1 mM, and 2.5 mM in the presence of heparin, hirudin peptide and PPS respectively, suggesting the increased catalytic activity is due to enhanced access to the primary specificity pocket. The positive influence of these ligands on des-ETW-thrombin was reversed in the presence of ATP or ADP; the latter has previously been shown to inhibit thrombin activity by blocking initial interaction with fibrinogen at exosite 1. Because the effect of heparin and PPS is similar to that of hirudin peptide, it is proposed that the most likely mechanism is that binding at the heparin-binding site (thrombin exosite 2) facilitates interaction at exosite 1 causing a conformational change which partially corrects the defective ground-state binding of the mutant thrombin. Although no effect was observed upon the activity of wild-type thrombin, our findings do provide further evidence of an allosteric property of thrombin which may control the geometry of, and access to, the primary specificity pocket.

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The role of surface charge on the accelerating action of heparin on the antithrombin III-inhibited activity of alpha-thrombin.

Cited by 53 publications

References 31 publications

A low-voltage electrokinetic nanochannel drug delivery system

A low-voltage electrokinetic nanochannel drug delivery system

Stability of Dendriplexes Formed by Anti-HIV Genetic Material and Poly(propylene imine) Dendrimers in the Presence of Glucosaminoglycans

Heparin enhances the catalytic activity of des-ETW-thrombin

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