Interactions of Paraoxonase-1 with Pharmacologically Relevant Carbamates

Mammalian paraoxonase-1 hydrolyses a very broad spectrum of esters such as certain drugs and xenobiotics. The aim of this study was to determine whether carbamates influence the activity of recombinant PON1 (rePON1). Carbamates were selected having a variety of applications: bambuterol and physostigmine are drugs, carbofuran is used as a pesticide, while Ro 02-0683 is diagnostic reagent. All the selected carbamates reduced the arylesterase activity of rePON1 towards the substrate S-phenyl thioacetate (PTA). Inhibition dissociation constants (Ki), evaluated by both discontinuous and continuous inhibition measurements (progress curves), were similar and in the mM range. The rePON1 displayed almost the same values of Ki constants for Ro 02-0683 and physostigmine while, for carbofuran and bambuterol, the values were approximately ten times lower and two times higher, respectively. The affinity of rePON1 towards the tested carbamates was about 3–40 times lower than that of PTA. Molecular modelling of rePON1-carbamate complexes suggested non-covalent interactions with residues of the rePON1 active site that could lead to competitive inhibition of its arylesterase activity. In conclusion, carbamates can reduce the level of PON1 activity, which should be kept in mind, especially in medical conditions characterized by reduced PON1 levels.

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Beneficial effect of oleoylated lipids on paraoxonase 1: protection against oxidative inactivation and stabilization

Biochemical Journal ◽

10.1042/bj20030663 ◽

2003 ◽

Vol 375 (2) ◽

pp. 275-285 ◽

Cited By ~ 41

Author(s):

S. Duy NGUYEN ◽

Dai-Eun SOK

Keyword(s):

Fatty Acids ◽

Oleic Acid ◽

Linoleic Acid ◽

Competitive Inhibition ◽

Protective Action ◽

Saturated Fatty Acids ◽

Density Lipoprotein ◽

Paraoxonase 1 ◽

Pon1 Activity ◽

Oxidative Inactivation

The effect of lipids on PON1 (paraoxonase 1), one of antioxidant proteins in high-density lipoprotein, was investigated in respect to inhibition, protection against oxidative inactivation, and stabilization. When the effect of lipids on the PON1 activity was examined, a remarkable inhibition was expressed by polyenoic fatty acids (C18:2–C20:5). Linoleic acid, the most potent (Ki, 3.8 μM), showed competitive inhibition. Next, various lipids were examined for prevention against the inactivation of PON1 by ascorbate/Cu2+, which caused a remarkable (≥90%) inactivation of PON1. Compared with saturated fatty acids (C6–C18), exhibiting a modest protection (9–40%), monoenoic acids (C16:1–C20:1) showed a greater maximal protective effect (Emax, 70–82%), with oleic acid being the most effective (EC50, 2.7 μM). In contrast, polyenoic acids showed no protection. Noteworthy, linoleic acid prohibited the protective action of oleic acid non-competitively. In the structure–activity relationship, a negatively charged group seems to be required for the protective action. Consistent with this, dioleoylphosphatidylglycerol, negatively charged, was more protective than dioleoylphosphatidylcholine. These data, together with requirement of Ca2+ (EC50, 0.6 μM) for the protective action, may support the existence of a specific site responsible for the protective action. A similar protective action of lipids was also observed in the inactivation of PON1 by ascorbate/Fe2+, peroxides or p-hydroxymercuribenzoate. Separately, PON1 was stabilized by oleic acid or oleoylated phospholipids, in combination with Ca2+, but not linoleic acid. These results suggest that in contrast to an adverse action of linoleic acid, monoenoic acids or their phospholipid derivatives play a beneficial role in protecting PON1 from oxidative inactivation as well as in stabilizing PON1.

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Destabilization is as important as binding

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1993.0112 ◽

1993 ◽

Vol 345 (1674) ◽

pp. 3-10 ◽

Cited By ~ 3

Keyword(s):

Binding Energy ◽

Gibbs Energy ◽

Active Site ◽

Electrostatic Interactions ◽

Large Fraction ◽

Geometric Distortion ◽

Substrate Complex ◽

Enzyme Substrate ◽

Non Covalent Interactions ◽

Covalent Interactions

Enzymes make use of non-covalent interactions with their substrates to bring about a large fraction of their catalytic activity. These interactions must destabilize, or increase the Gibbs energy, of the substrate in the active site in order that the transition state can be reached easily. This destabilization may be brought about by utilization of the intrinsic binding energy between the active site and the bound substrate by desolvation of charged groups, geometric distortion, electrostatic interactions and, especially, loss of entropy in the enzyme-substrate complex. These mechanisms are described by interaction energies and require utilization of the intrinsic binding energy that is realized from non-covalent interactions between the enzyme and substrate. Receptors and coupled vectorial processes, such as muscle contraction and active transport, utilize binding energy similarly to avoid large peaks and valleys along the Gibbs energy profile of the reaction under physiological conditions.

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Structure of N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide by combined X-ray powder diffraction, 13C solid-state NMR and molecular modelling

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768110039327 ◽

2010 ◽

Vol 66 (6) ◽

pp. 615-621 ◽

Cited By ~ 7

Author(s):

Adriana Hangan ◽

Gheorghe Borodi ◽

Xenia Filip ◽

Carmen Tripon ◽

Cristian Morari ◽

...

Keyword(s):

Solid State ◽

Powder Diffraction ◽

Molecular Modelling ◽

Solid State Nmr ◽

X Ray ◽

Structure Solution ◽

Non Covalent Interactions ◽

Projector Augmented Wave ◽

Covalent Interactions ◽

Microcrystalline Powder

The crystal structure solution of the title compound is determined from microcrystalline powder using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct-space methods with information from 13C solid-state NMR (SSNMR), and molecular modelling using the GIPAW (gauge including projector augmented-wave) method. The space group is Pbca with one molecule in the asymmetric unit. The proposed methodology proves very useful for unambiguously characterizing the supramolecular arrangement adopted by the N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide molecules in the crystal, which consists of extended double strands held together by C—H...π non-covalent interactions.

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Preparation of alginate–chitosan–cyclodextrin micro- and nanoparticles loaded with anti-tuberculosis compounds

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.7.112 ◽

2016 ◽

Vol 7 ◽

pp. 1208-1218 ◽

Cited By ~ 7

Author(s):

Albert Ivancic ◽

Fliur Macaev ◽

Fatma Aksakal ◽

Veaceslav Boldescu ◽

Serghei Pogrebnoi ◽

...

Keyword(s):

Active Site ◽

Acyl Carrier Protein ◽

Antimycobacterial Activity ◽

Frontier Molecular Orbital ◽

Molecular Orbital Calculations ◽

Activity Data ◽

Active Inhibitor ◽

Non Covalent Interactions ◽

Covalent Interactions ◽

Nanoparticulate Systems

This paper describes the synthesis and application of alginate–chitosan–cyclodextrin micro- and nanoparticulate systems loaded with isoniazid (INH) and isoconazole nitrate (ISN) as antimycobacterial compounds. Preparation and morphology of the obtained particles, as well as antimycobacterial activity data of the obtained systems are presented. Docking of isoconazole into the active site of enoyl–acyl carrier protein reductase (InhA) of Mycobacetrium tuberculosis was carried out in order to predict the binding affinity and non-covalent interactions stabilizing the InhA–isoconazole complex. To assess these interactions, frontier molecular orbital calculations were performed for the active site of InhA and isoconazole obtained from docking. Isoconazole was predicted to be an active inhibitor of InhA with the analysis of the molecular docking and electron density distribution. It has been detected that alginate–chitosan–cyclodextrin microparticulate systems loaded with INH and ISN are as effective as pure INH applied in higher dosages.

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Proteolytic resistance conferred to fibrinogen by von Willebrand factor

Thrombosis and Haemostasis ◽

10.1160/th09-07-0420 ◽

2010 ◽

Vol 103 (02) ◽

pp. 291-298 ◽

Cited By ~ 7

Author(s):

Anna Tanka-Salamon ◽

Raymund Machovich ◽

Erzsebet Komorowicz ◽

Krasimir Kolev

Keyword(s):

Von Willebrand Factor ◽

Active Site ◽

Competitive Inhibition ◽

Dissociation Constants ◽

Degradation Products ◽

Kinetic Measurements ◽

Proteolytic Resistance ◽

Von Willebrand ◽

Willebrand Factor

SummaryThe formation of platelet-rich thrombi under high shear rates requires both fibrinogen and von Willebrand factor (VWF) as molecular adhesives between platelets. We attempted to describe the role of VWF as a potential substrate and modulator of the fibrinolytic system using binding assays, as well as kinetic measurements on the cleavage of fibrin(ogen) and a synthetic plasmin substrate (Spectrozyme-PL). The similar dissociation constants for the binding of plasminogen, plasmin, and active site-blocked plasmin onto immobilised VWF suggest that the primary binding site in plasmin(ogen) is not the active site. The progressive loss of clottability and generation of degradation products during fibrinogen digestion with plasmin were delayed in the presence of VWF at physiological concentrations, while VWF cleavage was not detectable. Determination of kinetic parameters for fibrinogen degradation by plasmin, miniplasmin and microplasmin showed that VWF did not modify the Km, whereas kcat values decreased with increasing VWF concentrations following the kinetic model of non-competitive inhibition. Inhibitory constants calculated for VWF were in the range of its physiological plasma concentration (5.4 μg/ml, 5.7 μg/ml and 10.0 μg/ ml for plasmin, miniplasmin and microplasmin, respectively) and their values suggested a modulating role of the kringle 5 domain in the interaction between VWF and (mini)plasmin. VWF had no effect on the amidolytic activity of plasmin on Spectrozyme-PL, or on fibrin dissolution by (mini)plasmin. Our data suggest that VWF, while a poor plasmin substrate relative to fibrinogen, protects fibrinogen against degradation by plasmin preserving its clottability in plasma and its adhesive role in platelet-rich thrombi.

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Screening for Potential Traditional Herbal Inhibitors Against 3-Chymotrypsin-Like Main Protease (3CLpro) from Four Different Coronaviruses-: An in-silico Approach

Coronaviruses ◽

10.2174/2666796702666210216142508 ◽

2021 ◽

Vol 02 ◽

Author(s):

Prachi Singh ◽

Ardra P ◽

Hariprasad V.R. ◽

Babu U.V. ◽

Mohamed Rafiq ◽

...

Keyword(s):

Binding Affinity ◽

Broad Spectrum ◽

Active Site ◽

Dissociation Constants ◽

Substrate Binding ◽

Binding Pocket ◽

Health Concern ◽

Ocimum Sanctum ◽

Prunella Vulgaris ◽

Main Protease

Background: The recent outbreak of the COVID-19 pandemic has raised a global health concern due to the unavailability of any vaccines or drugs. The repurposing of traditional herbs with broad-spectrum anti-viral activity can be explored to control or prevent a pandemic. Objective: The 3-chymotrypsin-like main protease (3CLpro), also referred to as the “Achilles’ heel” of the coronaviruses (CoVs), is highly conserved among CoVs and is a potential drug target. 3CLpro is essential for the virus’s life cycle. The objective of the study was to screen and identify broad-spectrum natural phytoconstituents against the conserved active site and substrate-binding site of 3CLpro of HCoVs. Methods: Herein, we applied the computational strategy based on molecular docking to identify potential phytoconstituents for the non-covalent inhibition of the main protease 3CLpro from four different CoVs, namely, SARS-CoV-2, SARS-CoV, HCoV-HKU1, and HCoV-229E. Results: Our study shows that natural phytoconstituents in Triphala (a blend of Emblica Officinalis fruit, Terminalia bellerica fruit, and Terminalia chebula fruit), namely chebulagic acid, chebulinic acid, and elagic acid, exhibited the highest binding affinity and lowest dissociation constants (Ki), against the conserved 3CLpro main protease of SARSCoV-2, SARS-CoV, HCoV-HKU1, and HCoV-229E. Besides, phytoconstituents of other herbs like Withania somnifera, Glycyrrhiza glabra, Hyssopus officinalis, Camellia sinensis, Prunella vulgaris, and Ocimum sanctum also showed good binding affinity and lower Ki against the active site of 3CLpro. The top-ranking phytoconstituents’ binding interactions clearly showed a strong and stable interactions with amino acid residues in the catalytic dyad (CYS-HIS) and substrate-binding pocket of the 3CLpro main proteases. Conclusion: This study provides a valuable scaffold for repurposing traditional herbs with anti-CoV activity to combat SARS-CoV-2 and other HCoVs until the discovery of new therapies.

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Paraoxonase-1 and myeloperoxidase correlate with vascular biomarkers in overweight patients with newly diagnosed untreated hyperlipidaemia

VASA ◽

10.1024/0301-1526/a000643 ◽

2017 ◽

Vol 46 (5) ◽

pp. 370-376 ◽

Cited By ~ 2

Author(s):

Anita Szentpéteri ◽

Noémi Zsíros ◽

Viktória E. Varga ◽

Hajnalka Lőrincz ◽

Mónika Katkó ◽

...

Keyword(s):

Adhesion Molecule ◽

Oxidized Ldl ◽

Vascular Complications ◽

Cd40 Ligand ◽

Paraoxonase 1 ◽

Intercellular Adhesion Molecule ◽

Pon1 Activity ◽

Intercellular Adhesion Molecule 1 ◽

Inflammatory Parameters ◽

Vascular Biomarkers

Abstract. Background: In hyperlipidaemic state, increased levels of myeloperoxidase (MPO) and decreased paraoxonase-1 (PON1) activity have been reported; however, their relationships with other atherosclerotic biomarkers have not been completely clarified. Patients and methods: Serum concentrations of lipid and inflammatory parameters, MPO levels, and PON1 activities were investigated in 167 untreated hyperlipidaemic patients with and without vascular complications and in 32 healthy controls. Additionally, levels of CD40 ligand (sCD40L) and asymmetric dimethyl arginine (ADMA), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1, and oxidized LDL were determined. Results: We found elevated C-reactive protein (CRP), ADMA, sCD40L, sICAM-1 concentrations, and higher MPO levels in patients with vascular complications compared to those without. The PON1 arylesterase activity correlated negatively with sCD40L, ADMA, and sICAM-1 levels, respectively. In contrast, MPO concentrations showed positive correlations with sCD40L, ADMA, and sICAM-1 levels, respectively. Conclusions: It can therefore be stated that PON1 activity and MPO level correlate strongly with the vascular biomarkers, highlighting the importance of the HDL-associated pro- and antioxidant enzymes in the development of endothelial dysfunction and atherogenesis.

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