15139-21-6Relevant articles and documents
The identification of new metallo-β-lactamase inhibitor leads from fragment-based screening
Vella, Peter,Hussein, Waleed M.,Leung, Eleanor W.W.,Clayton, Daniel,Ollis, David L.,Miti?, Nata?a,Schenk, Gerhard,McGeary, Ross P.
, p. 3282 - 3285 (2011)
The emergence of metallo-β-lactamases (MBLs) capable of hydrolysing a broad spectrum of β-lactam antibiotics is particularly concerning for the future treatment of bacterial infections. This work describes the discovery of lead compounds for the development of new inhibitors using a competitive colorimetric assay based on the chromogenic cephalosporin CENTA, and a 500 compound Maybridge library suitable for fragment-based screening. The interactions between identified inhibitory fragments and the active site of the MBL from Klebsiella pneumoniae and Pseudomonas aeruginosa were probed by in silico docking studies.
Protective effects of piceatannol on methylglyoxal-induced cytotoxicity in MC3T3-E1 osteoblastic cells
Suh, Kwang Sik,Chon, Suk,Choi, Eun Mi
, p. 712 - 723 (2018)
Methylglyoxal (MG) is a reactive α-oxoaldehyde that increases under diabetic conditions and subsequently contributes to the complications associated with this disease. Piceatannol is a naturally occurring analogue of resveratrol that possesses multiple biological functions. The present study investigated the effects of piceatannol on MG-induced cytotoxicity in MC3T3-E1 osteoblastic cells. Piceatannol significantly restored MG-induced reductions in cell viability and reduced lactate dehydrogenase release in MG-treated MC3T3-E1 osteoblastic cells, which suggests that it suppressed MG-induced cytotoxicity. Piceatannol also increased glyoxalase I activity and glutathione levels in MG-treated cells, which indicates that it enhanced the glyoxalase system and thus cellular protection. The present study also showed that piceatannol inhibited the generation of inflammatory cytokines and reactive oxygen species and ameliorated mitochondrial dysfunction induced by MG. Furthermore, piceatannol treatment significantly reduced the levels of endoplasmic reticulum stress and autophagy induced by MG. Therefore, piceatannol could be a potent option for the development of antiglycating agents for the treatment of diabetic osteopathy.
Effect of N-B transition on the microenvironment surrounding 34Cys in human serum albumin
Narazaki, Ryuichi,Maruyama, Toru,Otagiri, Masaki
, p. 452 - 454 (1997)
The effect of pH on the microenvironment surrounding 34Cys in human serum albumin (HSA) has been studied using acrylodan, a Cys-specific fluorescence probe. The reactivity of 34Cys with 5,5'-dithiobis(2-nitro benzoic acid) (DTNB) followed a pseudo-first-order reaction, and the increase in reactivity was dependent on pH and oleate content. Compared with the N- form of HSA-acrylodan conjugate (pH 6.2), the B-form (pH 8.4) has a blue- shifted Em(max) and enhanced fluorescence intensity derived from acrylodan covalently attached to 34Cys suggesting that the exposure around 34Cys in the B-form was less than that in the N-form. The conformational change induced by fatty acid increased the exposure around 34Cys, while that induced by an increase in pH decreased it. Further, since the effect of oleate on the fluorescence of acrylodan was nearly the same for both conformers, the effects of pH and oleate on the microenvironment surrounding 34Cys should be independent and additive. We concluded that the increase of reactivity of 34Cys as a function in increasing pH may well be related to an increase in mercaptide ion content.
Characterization and in vitro functional analysis of thioredoxin glutathione reductase from the liver fluke Opisthorchis viverrini
Chaiyadet, Sujittra,Laha, Thewarach,Laohaviroj, Marut,Plumworasawat, Sirikanya,Prum, Satya,Saichua, Prasert,Sripa, Banchob,Suttiprapa, Sutas,Thanan, Raynoo
, (2020)
The carcinogenic liver fluke Opisthorchis viverrini causes several hepatobiliary diseases including a bile duct cancer-cholangiocarcinoma (CCA), which is a major public health problem in many countries in the Greater Mekong Sub-region. Praziquantel is the main drug against this parasite, however, reduced drug efficacy has been observed in some endemic areas. Therefore, alternative drugs are needed to prepare for praziquantel resistance in the future. The selenoprotein thioredoxin glutathione reductase (TGR) enzyme, which plays a crucial role in cellular redox balance of parasitic flatworms, has been shown as a potential drug target against these parasites. Hence, this study aimed to investigate the TGR of O. viverrini and assess its potential as a drug target. An open reading frame (ORF) that encodes O. viverrini TGR (Ov-TGR) was cloned from an O. viverrini cDNA library and the nucleotide were sequenced. The 1,812 nucleotides of the Ov-TGR full ORF encoded a polypeptide of 603 amino acid residues with a predicted molecular mass of 66 kDa. The putative amino acid sequence shared 55–96.8percent similarities with TGRs from other helminths and mammals. Phylogenetic analysis revealed a close relationship of Ov-TGR with that of other trematodes. The ORF of Ov-TGR was inserted into pABC2 plasmid and transformed into Escherichia coli strain C321.ΔA to facilitate selenocysteine incorporation. The recombinant Ov-TGR (rOv-TGR-SEC) was expressed as a soluble protein and detected as a dimer form in the non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Its thioredoxin reductase (TrxR) and glutathione reductase (GR) activities were detected using DTNB, Trx and GSSG substrates with the Michaelis constant (Km) of 292.6 ± 52.3 μM, 8.09 ± 1.91 μM and 13.74 ± 1.2 μM, respectively. The TGR enzyme activities were effectively inhibited by a well-known inhibitor, auranofin in a dose-dependent manner. Moreover, auranofin expressed a lethal toxic effect on both newly excysted juveniles (NEJs) and adult worms of O. viverrini in vitro. Taken together, these results indicated that Ov-TGR is crucial for O. viverrini survival and maybe a potential target for the development of novel agents against opisthorschiasis.
CENTA as a chromogenic substrate for studying β-lactamases
Bebrone, Carine,Moali, Catherine,Mahy, Florence,Rival, Sandrine,Docquier, Jean Denis,Rossolini, Gian Maria,Fastrez, Jacques,Pratt, Rex F.,Frere, Jean-Marie,Galleni, Moreno
, p. 1868 - 1871 (2001)
CENTA, a chromogenic cephalosporin, is readily hydrolyzed by β-lactamases of all classes except for the Aeromonas hydrophila metalloenzyme. Although it cannot practically be used for the detection of β-lactamase-producing strains on agar plates, it should be quite useful for kinetic studies and the detection of the enzymes in crude extracts and chromatographic fractions.
Fluorescence detection of the nitric oxide-induced structural change at the putative nitric oxide sensing segment of TRPC5
Mori, Yasuo,Morii, Takashi,Nakata, Eiji,Saimura, Masayuki,Sakaguchi, Reiko,Tajima, Shunsuke
, (2020)
The plausible nitric oxide (NO)-sensing module of TRPC5 was incorporated in a enhanced green fluorescent protein (EGFP) to evaluate its conformational change as an optical response upon the reaction with NO. Two cysteine residues located in the NO-sensing module have been proposed to form a disulfide bond through S-nitrosylation of the thiol group by NO. Modification of the cysteine residues by NO resulted a ratiometric change of EGFP emission through transducing the conformational change of NO-sensing module to the EGFP chromophore. The oxidized form of NO-sensing module fused EGFP changed the intensity of emission spectra upon reduction of the disulfide bond at the NO-reactive module. The NO-sensing module fused EGFP in its reduced form avidly reacted with NO and realized the ratiometric fluorescence intensity changes depending on the formation of disulfide bond. These results support the notion that NO induces a conformational change at the putative NO-sensing segment of TRPC5, and provide a prototype for the genetically encoded cellular NO sensors.
Biochemical and thermodynamic comparison of the selenocysteine containing and non-containing thioredoxin glutathione reductase of Fasciola gigantica
Kalita, Parismita,Shukla, Harish,Shukla, Rohit,Tripathi, Timir
, p. 1306 - 1316 (2018)
The thiol-disulfide redox metabolism in platyhelminth parasites depends entirely on a single selenocysteine (Sec) containing flavoenzyme, thioredoxin glutathione reductase (TGR) that links the classical thioredoxin (Trx) and glutathione (GSH) systems. In the present study, we investigated the catalytic and structural properties of different variants of Fasciola gigantica TGR to understand the role of Sec. The recombinant full-length Sec containing TGR (FgTGRsec), TGR without Sec (FgTGR) and TGRsec without the N-terminal glutaredoxin (Grx) domain (?NTD-FgTGRsec) were purified to homogeneity. Biochemical studies revealed that Sec597 is responsible for higher thioredoxin reductase (TrxR) and glutathione reductase (GR) activity of FgTGRsec. The N-terminal Grx domain was found to positively regulate the DTNB-based TrxR activity of FgTGRsec. The FgTGRsec was highly sensitive to inhibition by auranofin (AF). The structure of FgTGR was modeled, and the inhibitor AF was docked, and binding sites were identified. Unfolding studies suggest that all three proteins are highly cooperative molecules since during GdnHCl-induced denaturation, a monophasic unfolding of the proteins without stabilization of any intermediate is observed. The Cm for GdnHCl induced unfolding of FgTGR was higher than FgTGRsec and ?NTD-FgTGRsec suggesting that FgTGR without Sec was more stable in solution than the other protein variants. The free energy of stabilization for the proteins was also determined. To our knowledge, this is also the first report on unfolding and stability analysis of any TGR.
On the Cleavage of Ellman's Reagent by Dithonite in the Presence of Dioctadecyldimethylammonium Chloride Surfactant Vesicles Laced with Cholesterol
Huffman, Robert W.,McBride, Phil,Brown, David M.
, p. 1633 - 1637 (1994)
Ellman's reagent (I) is distributed between the outer aqueous interface and the interior bilayer of DODAC vesicles upon contact when added to presonicated aqueous DODAC suspensions.This distribution also extends to the inner aqueous interface in about 10 min.This suspension reacts with aqueous alkaline sodium dithionite in two kinetic processes.The first process involves the bimolecular cleavage of I at the outer aqueous interface instantaneously.This is followed by a slow reaction of the same due to leakage of the bilayer-embedded substrate to the outer interface.This condition changes, however, when the DODAC vesicles are laced with cholesterol by cosonication of the aqueous solutions.Both Ellman's reagent and the reduced anion II product of cleavage by dithionite now are impermeable to this membrane but the protonated III does penetrate the bilayer.This result is indicated by loss of absorbance at 440 nm concurrent with gain in absorbance at 320 nm upon contact between III and cholesterol-laced vesicles.This result is interpreted in terms of the known permeability changes accompanying the incorporation of cholesterol into the vesicles.Thus Ellman's reaggent (I) can be encapsulated by DODAC vesicles if they contain cholesterol in such a way that they are unreachable by dithionite and lyate species.
Enzymatic spectrophotometric method for aflatoxin B detection based on acetylcholinesterase inhibition
Arduini, Fabiana,Errico, Ilenia,Amine, Aziz,Micheli, Laura,Palleschi, Giuseppe,Moscone, Danila
, p. 3409 - 3415 (2007)
A new method for aflatoxin B (AFB) determination is proposed. The AFB determination is based on acetylcholinesterase (AChE) inhibition, and the AChE residual activity is determined using the colorimetric method (Ellman's method). Cholinesterases (ChEs) from various sources were tested using AFB1 as reference aflatoxin. AChE from electric eel has shown the highest sensitivity to AFB1, and it was chosen for the rest of the work. To select and optimize the analytical procedures, an investigation on the type of AChE inhibition by AFB1 was carried out. The AChE degree of inhibition by AFB1 was independent of the incubation time and the enzyme concentrations, showing the reversibility of the inhibition. This reversibility of the inhibition permits a rapid analysis of AFB1, requiring only 3 min. For the development of the AFB1 assay, the pH, the time of reaction, temperature, and substrate concentration were evaluated and optimized. The linear range of 10-60 ng mL-1 was determined. To evaluate the selectivity of this method, the cross-reactivity with other aflatoxins such as aflatoxin B2, aflatoxin G1, aflatoxin G2, and aflatoxin M1 was investigated. Finally, the suitability of the assay for AFB1 quantification in barley was evaluated. This study shows a new approach to detect anatoxins based on enzyme inhibition and has advantages such as the ease of use, rapidity, and cost effectiveness. Thus, it could find a possible use as a screening method for this type of mycotoxins.
Antioxidant activity and inhibition of human neutrophil oxidative burst mediated by arylpropionic acid non-steroidal anti-inflammatory drugs
Costa, David,Moutinho, Luis,Lima, Jose Luis Fontes Costa,Fernandes, Eduarda
, p. 1659 - 1670 (2006)
It has been suggested that the anti-inflammatory activity of some non-steroidal anti-inflammatory drugs (NSAIDs) may be partly due to their ability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS), as well as to inhibit the respiratory burst of neutrophils triggered by various activating agents. Therefore, the aim of the present work was to evaluate and compare the potential scavenging activity for an array of ROS (O2.-, H2O2, HO., ROO. and HOCl) and RNS (.NO and ONOO-) using in vitro non-cellular screening systems as well as a cellular screening system (human neutrophil oxidative burst), mediated by the arylpropionic acid derivatives (APAs) NSAIDs ibuprofen, flurbiprofen, fenoprofen, fenbufen, ketoprofen, naproxen and indoprofen. The results obtained in the present work demonstrate that under the present experimental conditions, many of the studied APA NSAIDs showed O2.- scavenging activity (fenbufen≈ flurbiprofen≈indoprofen≈ketoprofen), H2O2 (ketoprofen≈indoprofen≈fenbufen>flurbiprofen>naproxen), HO . (fenoprofen≈ibuprofen>fenbufen≈flurbiprofen> ketoprofen>indoprofen≈naproxen), .NO (indoprofen> naproxen), ONOO- (indoprofen>naproxen>fenoprofen≈flurbiprofen≈ ibuprofen), as well as inhibit myeloperoxidase (MPO) activity (indoprofen) and scavenge human neutrophil derived ROS (ketoprofen>indoprofen >fenbufen>flurbiprofen). The observed effects, if confirmed in vivo, may strongly contribute to the antiinflammatory therapeutical activity observed with these NSAIDs.
Highly sensitive DNA methylation analysis at CpG resolution by surface-enhanced Raman scattering via ligase chain reaction
Wang, Yuling,Wee, Eugene J. H.,Trau, Matt
, p. 10953 - 10956 (2015)
Sensitive and accurate DNA methylation analysis at CpG resolution was demonstrated using surface-enhanced Raman scattering (SERS) via ligase chain reaction (LCR). The method was sensitive to 10% changes in methylation and the accuracy of methylation estimates in cells and serum DNA validated with sequencing. The LCR/SERS approach may have broad applications as an alternative (epi)genetic detection method.
Novel solid-phase reagents for facile formation of intramolecular disulfide bridges in peptides under mild conditions
Annis, Ioana,Chen, Lin,Barany, George
, p. 7226 - 7238 (1998)
The controlled formation of intramolecular disulfide bridges in peptides, while avoiding unwanted oligomerization, is a significant challenge. Ellman's reagent, 5,5'-dithiobis(2-nitrobenzoic acid), was developed originally in the context of an assay for measuring free thiol concentration under physiological conditions. The present studies demonstrate that this reagent, when bound through two sites to a suitable solid support (PEG-PS, modified Sephadex, or controlled-pore glass), is an effective mild oxidizing reagent that promotes the formation of disulfide bridges. Rates and yields of the reactions were determined as a function of pH, excess of oxidizing reagent, resin loading, and parent support, for the preparation of oxytocin and deaminooxytocin (9 residues, disulfide bridge between residues 1 and 6), somatostatin (14 residues, disulfide bridge between residues 3 and 14), α-conotoxin SI (13 residues, disulfide bridges between residues 2 and 7; 3 and 13), and apamin (18 residues, disulfide bridges between residues 1 and 11; 3 and 15). Cystine dimers of these peptide models formed, if at all, in relatively low amounts. Use of solid-phase Ellman's reagents to oxidize the linear precursors of conotoxin or apamin (tetrathiols) gave as the main products the correctly paired regioisomers. Particular advantages of the overall approach include fast reaction rates over a wide range of pH, from 2.7 to 6.6; easy purification of disulfide-containing products; and the specificity and reusability of the reagents.
Degani,Patchornik
, p. 2727 (1971)
Synthesis, characterization and biological activity of bis[3-ethyl-4-aryl-5-(2-methoxypyridin-5-yl)-1-propyl-1,3-dihydro-2H-imidazol-2-ylidene]gold(i) complexes
Gallati, Caroline Marie,Goetzfried, Sina Katharina,Ortmeier, Anna,Sagasser, Jessica,Wurst, Klaus,Hermann, Martin,Baecker, Daniel,Kircher, Brigitte,Gust, Ronald
, p. 4270 - 4279 (2021)
A series of bis[3-ethyl-4-aryl-5-(2-methoxypyridin-5-yl)-1-propyl-1,3-dihydro-2H-imidazol-2-ylidene]gold(i) complexes (2a-f) containing methyl, fluoro or methoxy substituents at various positions in the 4-aryl ring was synthesized and evaluated for their anti-cancer properties in A2780 (wild-type and Cisplatin-resistant) ovarian carcinoma as well as LAMA 84 (imatinib-sensitive and -resistant) and HL-60 leukemia cell lines. The bis-NHC gold(i) complexes were more active compared to their related mono-NHC gold(i) analogues and reduced proliferation and metabolic activity in a low micromolar range. With the exception of2d(3-F), the compounds displayed higher potency than the established drugs Auranofin and Cisplatin. The lack of effects against non-cancerous lung fibroblast SV-80 cells indicated a high selectivity towards tumor cells. All tested complexes generated reactive oxygen species in A2780cis cells; however, the induction of apoptosis was very low. Furthermore, thioredoxin reductase is not the main target of these complexes, because its inhibition pattern did not correlate with their biological activity.
An Ultrasmall Fe3O4-Decorated Polydopamine Hybrid Nanozyme Enables Continuous Conversion of Oxygen into Toxic Hydroxyl Radical via GSH-Depleted Cascade Redox Reactions for Intensive Wound Disinfection
Deng, Le,Gong, Minhui,Hai, Luo,He, Dinggeng,Li, Huan,Li, Yaoyao,Tang, Zifeng,Wang, Zefeng,Xiao, Jiayu
, (2021/12/22)
Nanozyme-based chemodynamic therapy (CDT) for fighting bacterial infections faces several major obstacles including low hydrogen peroxide (H2O2) level, over-expressed glutathione (GSH) in infected sites, and inevitable damage to healthy tissue with abundant nonlocalized nanozymes. Herein, a smart ultrasmall Fe3O4-decorated polydopamine (PDA/Fe3O4) hybrid nanozyme is demonstrated that continuously converts oxygen into highly toxic hydroxyl radical (?OH) via GSH-depleted cascade redox reactions for CDT-mediated bacterial elimination and intensive wound disinfection. In this system, photonic hyperthermia of PDA/Fe3O4 nanozymes can not only directly damage bacteria, but also improve the horseradish peroxidase-like activity of Fe3O4 decorated for CDT. Surprisingly, through photothermal-enhanced cascade catalytic reactions, PDA/Fe3O4 nanozymes can consume endogenous GSH for disrupting cellular redox homeostasis and simultaneously provide abundant H2O2 for improving ?OH generation, ultimately enhancing the antibacterial performance of CDT. Such PDA/Fe3O4 can bind with bacterial cells, and reveals excellent antibacterial property against both Staphylococcus aureus and Escherichia coli. Most interestingly, PDA/Fe3O4 nanozymes can be strongly retained in infected sites by an external magnet for localized long-term in vivo CDT and show minimal toxicity to healthy tissues and organs. This work presents an effective strategy to magnetically retain the therapeutic nanozymes in infected sites for highly efficient CDT with good biosafety.
