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1.
Phys Chem Chem Phys ; 22(8): 4464-4480, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32057044

RESUMO

Infection by human immunodeficiency virus type 1 (HIV-1) not only destroys the immune system bringing about acquired immune deficiency syndrome (AIDS), but also induces serious neurological diseases including behavioral abnormalities, motor dysfunction, toxoplasmosis, and HIV-1 associated dementia. The emergence of HIV-1 multidrug-resistant mutants has become a major problem in the therapy of patients with HIV-1 infection. Focusing on the wild type (WT) and G48T/L89M mutated forms of HIV-1 protease (HIV-1 PR) in complex with amprenavir (APV), indinavir (IDV), ritonavir (RTV), and nelfinavir (NFV), we have investigated the conformational dynamics and the resistance mechanism due to the G48T/L89M mutations by conducting a series of molecular dynamics (MD) simulations and free energy (MM-PBSA and solvated interaction energy (SIE)) analyses. The simulation results indicate that alterations in the side-chains of G48T/L89M mutated residues cause the inner active site to increase in volume and induce more curling of the flap tips, which provide the main contributions to weaker binding of inhibitors to the HIV-1 PR. The results of energy analysis reveal that the decrease in van der Waals interactions of inhibitors with the mutated PR relative to the wild-type (WT) PR mostly drives the drug resistance of mutations toward these four inhibitors. The energy decomposition analysis further indicates that the drug resistance of mutations can be mainly attributed to the change in van der Waals and electrostatic energy of some key residues (around Ala28/Ala28' and Ile50/Ile50'). Our work can give significant guidance to design a new generation of anti-AIDS inhibitors targeting PR in the therapy of patients with HIV-1 infection.


Assuntos
Protease de HIV/metabolismo , Simulação de Dinâmica Molecular , Fármacos Anti-HIV/química , Fármacos Anti-HIV/metabolismo , Carbamatos/química , Carbamatos/metabolismo , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/genética , Protease de HIV/genética , Indinavir/química , Indinavir/metabolismo , Conformação Molecular , Mutação , Nelfinavir/química , Nelfinavir/metabolismo , Ligação Proteica , Ritonavir/química , Ritonavir/metabolismo , Sulfonamidas/química , Sulfonamidas/metabolismo
2.
Eur J Med Chem ; 188: 111975, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31940507

RESUMO

Local changes in the structure of G-protein coupled receptors (GPCR) binders largely affect their pharmacological profile. While the sought efficacy can be empirically obtained by introducing local modifications, the underlining structural explanation can remain elusive. Here, molecular dynamics (MD) simulations of the eticlopride-bound inactive state of the Dopamine D3 Receptor (D3DR) have been clustered using a machine learning-based approach in the attempt to rationalize the efficacy change in four congeneric modulators. Accumulating extended MD trajectories of receptor-ligand complexes, we observed how the increase in ligand flexibility progressively destabilized the crystal structure of the inactivated receptor. To prospectively validate this model, a partial agonist was rationally designed based on structural insights and computational modeling, and eventually synthesized and tested. Results turned out to be in line with the predictions. This case study suggests that the investigation of ligand flexibility in the framework of extended MD simulations can assist and inform drug design strategies, highlighting its potential role as a powerful in silico counterpart to functional assays.


Assuntos
Carbamatos/metabolismo , Agonistas de Dopamina/metabolismo , Antagonistas de Dopamina/metabolismo , Piperazinas/metabolismo , Receptores de Dopamina D3/metabolismo , Animais , Sítios de Ligação , Células CHO , Carbamatos/química , Cricetulus , Agonistas de Dopamina/química , Antagonistas de Dopamina/química , Desenho de Drogas , Humanos , Ligantes , Aprendizado de Máquina , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Piperazinas/química , Conformação Proteica , Receptores de Dopamina D3/química , Salicilamidas/metabolismo
3.
Chemosphere ; 242: 125210, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31689638

RESUMO

Extraction of radioactive Cs from contaminated soil is a crucial aspect of remediation after nuclear accidents. For this purpose, we have developed a new type of ligand, carbamate-conjugated catechol, to assist in metal extraction by using supercritical CO2 (SCCO2). The synthesis process for this ligand is relatively simple, and the carbamate-conjugated catechol ligand dissolves well in SCCO2. The measured ligand distribution coefficient increased according to a power law with an exponent of 1.7 as the ligand concentration increased, indicating that approximately two ligand molecules are needed to extract one Cs ion. The roles of additives (ligand, co-ligand, and water) were limited when they were used separately, but the combination of these additives was important. We tested 27 combinations of these three additives for extracting Cs from artificially contaminated sea sand. A quantitative analysis indicated that the ligand had the strongest influence on Cs extraction, followed by water, and the co-ligand. The carbamate-conjugated catechol ligand was then used for Cs extraction from artificially contaminated real soil. Three types of soil were prepared: coarse soil (particle size = 0.5-1 mm), medium soil (particle size = 0.2-0.5 mm), and fine soil (particle size < 0.2 mm). The Cs fractions extracted from the coarse, medium, and fine soils were measured to be 95%, 91% and 70% of the Cs fraction extracted from sea sand, respectively, which indicates the existence of a surface area effect. Additionally, we suspect that Cs undergoes chemical interaction on the surface of real soil.


Assuntos
Carbamatos/química , Dióxido de Carbono/química , Catecóis/química , Césio/isolamento & purificação , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/isolamento & purificação , Ligantes , Metais/análise , Metais/isolamento & purificação , Tamanho da Partícula , Solo/química , Poluentes do Solo/análise , Água/análise , Água/química
4.
Anal Chim Acta ; 1094: 113-121, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761037

RESUMO

Alkaline phosphatase (ALP), an enzyme that catalyzes the hydrolysis of phosphate groups, is closely associated with many diseases, including bone disease, prostate cancer, and diabetes. Thus, new assays for ALP detection in live cells are needed to better understand its role in related biological processes. In this study, we constructed a novel near-infrared ratiometric fluorescent probe for detecting ALP activity with high sensitivity. The probe uses a new self-immolative mechanism that can achieve a rapid response (within 10 min) to ALP, detected as a spectral shift (from 580 to 650 nm). This method effectively avoids issues related to instrument variability, and the near-infrared fluorescence emission (650 nm) makes it more suitable for biological detection. Moreover, the high sensitivity (14-fold enhancement of the fluorescence ratio F650/F580) and low detection limit (0.89 U L-1) for ALP allows the probe to be adapted to complex biological environments. The assay was successfully performed using serum samples with a linear range of ALP of up to 150 U L-1. We used the developed probe to detect and image endogenous ALP in cells with satisfactory results, and we successfully used the probes to detect changes in endogenous ALP levels in zebrafish caused by drug-induced organ damage.


Assuntos
Fosfatase Alcalina/análise , Carbamatos/química , Corantes Fluorescentes/química , Organofosfatos/química , Acetaminofen/farmacologia , Animais , Carbamatos/síntese química , Carbamatos/toxicidade , Tetracloreto de Carbono/toxicidade , Bovinos , Teoria da Densidade Funcional , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Limite de Detecção , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Modelos Químicos , Organofosfatos/síntese química , Organofosfatos/toxicidade , Peixe-Zebra
5.
Chem Commun (Camb) ; 55(90): 13546-13549, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31647068

RESUMO

Drugs containing amine groups react with CO2 to form crystalline ammonium carbamates or carbamic acids. In this approach, both the cation and anion of the salt, or the neutral CO2 adduct, are derived from the parent drug, generating new crystalline versions in a 'masked' or prodrug form. It is proposed that this approach may serve as a valuable new tool in engineering the physical properties of drugs for formulation purposes.


Assuntos
Aminas/química , Compostos de Amônio/química , Carbamatos/química , Dióxido de Carbono/química , Ânions/química , Cátions/química , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular , Sais/química
6.
J Chromatogr A ; 1604: 460492, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31488295

RESUMO

The aim of this research study was to provide a more thorough understanding of the underlying mechanism and to broaden the application field of the recently introduced racemization method employing the amino acid derivatization tag 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC, AccQ) for heat-induced stereoisomerization of common amino acids as well as uniformly isotopically labeled [U-13C15N]-amino acids. The influence of different buffer types such as sodium borate buffer and sodium carbonate buffer as well as their pH and molarity on the racemization and deamidation of amino acids were investigated. It was found that a 0.4 M borate buffer with a pH of 8.0 +/- 0.2 was the most suitable derivatization as well as racemization buffer to ensure degradation free racemization of deamidation prone compounds such as glutamine. Hereby essential was the in-solution pH measurement before and after derivatization with AQC as well as after heat-induced racemization. This strategy provided further insight at which pH an actual racemization event was observed and when an unwanted deamidation of glutamine to glutamic acid occurred. In addition also the influence of the presence of oxygen during racemization was studied. In this context it was possible to determine ideal oxidation and racemization conditions for the production of scalemic mixtures of chiral isotopically labeled methionine AQC-DL-[U-13C15N]-Met as well as its oxidation products, AQC-DL-[U-13C15N]-Met-O and AQC-DL-[U-13C15N]-Met-O2. All stereoselective separations were performed on the zwitterionic Chiralpak ZWIX(+) column combined with HPLC-ESI-QTOF-MS analysis in positive ionization mode.


Assuntos
Amidas/química , Aminoácidos/química , Aminoquinolinas/química , Carbamatos/química , Tampões (Química) , Cromatografia Líquida de Alta Pressão/métodos , Concentração de Íons de Hidrogênio , Marcação por Isótopo , Oxirredução , Soluções , Estereoisomerismo
7.
Molecules ; 24(15)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370232

RESUMO

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease which is still poorly understood. The drugs currently used against AD, mainly acetylcholinesterase inhibitors (AChEI), are considered clinically insufficient and are responsible for deleterious side effects. AChE is, however, currently receiving renewed interest through the discovery of a chaperone role played in the pathogenesis of AD. But AChE could also serve as an activating protein for pleiotropic prodrugs. Indeed, inhibiting central AChE with brain-penetrating designed carbamates which are able to covalently bind to the enzyme and to concomitantly liberate active metabolites in the brain could constitute a clinically more efficient approach which, additionally, is less likely to cause peripheral side effects. We aim in this article to pave the road of this new avenue with an in vitro and in vivo study of pleiotropic prodrugs targeting both the 5-HT4 receptor and AChE, in order to display a neuroprotective activity associated with a sustained restoration of the cholinergic neurotransmission and without the usual peripheral side effects associated with classic AChEI. This plural activity could bring to AD patients effective, relatively safe, symptomatic and disease-modifying therapeutic benefits.


Assuntos
Acetilcolinesterase/genética , Doença de Alzheimer/tratamento farmacológico , Inibidores da Colinesterase/farmacologia , Pró-Fármacos/farmacologia , Acetilcolinesterase/química , Doença de Alzheimer/enzimologia , Doença de Alzheimer/patologia , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Carbamatos/química , Inibidores da Colinesterase/química , Humanos , Ligantes , Pró-Fármacos/química , Receptores 5-HT4 de Serotonina/genética
8.
Eur J Med Chem ; 181: 111578, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31401536

RESUMO

The research of novel antimycobacterial drugs represents a cutting-edge topic. Thirty phenolic N-monosubstituted carbamates, derivatives of salicylanilides and 4-chlorophenol, were investigated against Mycobacterium tuberculosis H37Ra, H37Rv including multidrug- and extensively drug-resistant strains, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium aurum and Mycobacterium smegmatis as representatives of nontuberculous mycobacteria (NTM) and for their cytotoxic and cytostatic properties in HepG2 cells. Since salicylanilides are multi-targeting compounds, we determined also inhibition of mycobacterial isocitrate lyase, an enzyme involved in the maintenance of persistent tuberculous infection. The minimum inhibitory concentrations were from ≤0.5 µM for both drug-susceptible and resistant M. tuberculosis and from ≤0.79 µM for NTM with no cross-resistance to established drugs. The presence of halogenated salicylanilide scaffold results into an improved activity. We have verified that isocitrate lyase is not a key target, presented carbamates showed only moderate inhibitory activity (up to 18% at a concentration of 10 µM). Most of the compounds showed no cytotoxicity for HepG2 cells and some of them were without cytostatic activity. Cytotoxicity-based selectivity indexes of several carbamates for M. tuberculosis, including resistant strains, were higher than 125, thus favouring some derivatives as promising features for future development.


Assuntos
Antituberculosos/química , Antituberculosos/farmacologia , Carbamatos/química , Carbamatos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Antituberculosos/síntese química , Carbamatos/síntese química , Células Hep G2 , Humanos , Isocitrato Liase/antagonistas & inibidores , Isocitrato Liase/metabolismo , Mycobacterium tuberculosis/enzimologia , Fenóis/síntese química , Fenóis/química , Fenóis/farmacologia , Salicilanilidas/síntese química , Salicilanilidas/química , Salicilanilidas/farmacologia , Tuberculose/tratamento farmacológico
9.
Chem Commun (Camb) ; 55(71): 10627-10630, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31429450

RESUMO

We report the synthesis of a novel hydroxyl-functionalised heteroleptic bis-NHC gold(i) complex that permits conjugation to various amines via carbamate bond formation. The resulting derivatives were studied in vitro using cell proliferation assays and fluorescent microscopic imaging of human cancer cell lines.


Assuntos
Aminas/química , Antineoplásicos/síntese química , Carbamatos/química , Complexos de Coordenação/síntese química , Corantes Fluorescentes/síntese química , Ouro/química , Células A549 , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Doxorrubicina/química , Humanos , Imagem Óptica , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Triazóis/química
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117313, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31277031

RESUMO

The binding to biosubstrates and micellar systems of pollutants as the polycyclic aromatic hydrocarbon (PAH) derivatives 1-aminopyrene (1-PyNH2) and 1-hydroxymethylpyrene (1-PyMeOH) and the carbamate-pesticides 1-naphthyl-N-methylcarbamate (carbaryl, CA) and methyl benzimidazol-2-ylcarbamate (carbendazim, CBZ) was analysed through an integrated strategy combining spectroscopy and quantum chemistry. As biosubstrates, natural DNA and bovine serum albumin (BSA) were taken into account for a thermodynamic analysis of the binding features through spectrophotometric and spectrofluorometric techniques. In all cases, a strong DNA interaction is present and intercalation is supposed as the major binding mode. For the PAH derivatives, DNA binding is found to be favoured under high salt conditions and BSA static quenching and binding with 1:1 stoichiometry occurs. The molecular structure and optical properties of 1-PyNH2, CA and CBZ together with their intercalated adducts in DNA were studied also by means of quantum chemical approach. The (TD)DFT calculations on intercalated dye/DNA adducts quantitatively reproduce the experimentally observed spectroscopic changes, thus confirming the intercalation hypothesis. The theoretical approach also provides information on the adducts' geometries and on the amount of charge transfer with DNA. Moreover, ultrafiltration tests in the presence of anionic (SDS), cationic (DTAC) and neutral (Triton X) micellar aggregates and liposomes provided insights into lipophilicity and cellular membrane affinity. PAH derivatives show high retention coefficient in all cases, whereas in the case of carbamate-pesticides micellar retention might be significantly reduced and is very limited in the case of liposomes.


Assuntos
Carbamatos/metabolismo , DNA/metabolismo , Lipossomos/metabolismo , Micelas , Praguicidas/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Soroalbumina Bovina/metabolismo , Animais , Carbamatos/química , Bovinos , Cinética , Conformação Molecular , Praguicidas/química , Hidrocarbonetos Policíclicos Aromáticos/química , Espectrometria de Fluorescência , Espectrofotometria
11.
Molecules ; 24(13)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277425

RESUMO

The reactions of 3-isoselenocyanato-2,2,5,5-tetramethylpyrrolidine-1-oxyl, 3-isoselenocyanatomethyl-2,2,5,5-tetramethyl-3-pyrrolidine-1-oxyl, and 4-isoselenocyanato-2,2,6,6-tetramethylpiperidine-1-oxyl with selected amines and alcohols give the corresponding novel nitroxyl selenoureas and selenocarbamates, all bearing a nitroxyl moiety. Synthesized selenoureas and selenocarbamates show significant activity against pathogenic fungi and bacteria. In contrast to piperidine nitroxides, pyrrolidine, five-membered nitroxyl selenoureas and selenocarbamates show excellent antifungal and antibacterial activity against pathogenic fungi and bacteria, respectively.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Carbamatos/farmacologia , Óxidos de Nitrogênio/síntese química , Óxidos de Nitrogênio/farmacologia , Compostos Organosselênicos/farmacologia , Ureia/análogos & derivados , Bactérias/efeitos dos fármacos , Carbamatos/síntese química , Carbamatos/química , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óxidos de Nitrogênio/química , Compostos Organosselênicos/síntese química , Compostos Organosselênicos/química , Ureia/síntese química , Ureia/química , Ureia/farmacologia
12.
Biomed Chromatogr ; 33(11): e4660, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31325166

RESUMO

In this study, a carboxyl group was introduced into the isoprocarb molecule to obtain an isoprocarb hapten, which was then coupled with a protein to obtain an artificial antigen. Three monoclonal antibody cell lines, 1D11, 6E6 and 1B5, were finally obtained by mouse immunization, cell fusion and subcloning, and the antibody produced by cell line 1B5 had the best affinity and sensitivity. The monoclonal antibody was highly sensitive and specific for isoprocarb, with an IC50 of 2.09 ng/ml and a cross-reactivity rate of <0.21%. By optimizing the indirect competitive (ic)-ELISA, the optimal conditions were determined to be pH 7.4, 0% methanol and 0.8% NaCl, the limit of detection value was 0.23 ng/ml, and the linear range of the ic-ELISA was 0.46-9.62 ng/ml. The recovery rate of the isoprocarb cucumber sample was 97-99% for the ic-ELISA method. In addition, we successfully developed an immunochromatographic test strip for the detection of isoprocarb residues. The cutoff values in phosphate-buffered saline and cucumber extract were 10 and 25 ng/ml, respectively. Both methods met the requirements for isoprocarb residue detection in agricultural products, and can be used for semiquantitative and qualitative analysis of isoprocarb in vegetables.


Assuntos
Anticorpos Monoclonais/metabolismo , Carbamatos/análise , Carbamatos/metabolismo , Ensaio de Imunoadsorção Enzimática/métodos , Imunoensaio/métodos , Especificidade de Anticorpos , Carbamatos/química , Coloide de Ouro/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
13.
Chemistry ; 25(58): 13309-13317, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31328310

RESUMO

The synthesis of the protected form of 2-methylthio-N6 -threonylcarbamoyl adenosine (ms2 t6 A) was developed starting from adenosine or guanosine by using the optimized carbamate method and, for the first time, an isocyanate route. The hypermodified nucleoside was subsequently transformed into the protected ms2 t6 A-phosphoramidite monomer and used in a large-scale synthesis of the precursor 17nt ms2 t6 A-oligonucleotide (the anticodon stem and loop fragment of tRNALys from T. brucei). Finally, stereochemically secure ms2 t6 A→ms2 ct6 A cyclization at the oligonucleotide level efficiently afforded a tRNA fragment bearing the ms2 ct6 A unit. The applied post-synthetic approach provides two sequentially homologous ms2 t6 A- and ms2 ct6 A-oligonucleotides that are suitable for further comparative structure-activity relationship studies.


Assuntos
Adenosina/análogos & derivados , Oligorribonucleotídeos/síntese química , RNA de Transferência/química , Treonina/análogos & derivados , Adenosina/química , Sequência de Bases , Carbamatos/química , Ciclização , Guanosina/química , Isocianatos/química , Conformação de Ácido Nucleico , Compostos Organofosforados/química , Relação Estrutura-Atividade , Treonina/síntese química , Treonina/química
14.
Elife ; 82019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31343405

RESUMO

ATP-sensitive potassium (KATP) channels composed of a pore-forming Kir6.2 potassium channel and a regulatory ABC transporter sulfonylurea receptor 1 (SUR1) regulate insulin secretion in pancreatic ß-cells to maintain glucose homeostasis. Mutations that impair channel folding or assembly prevent cell surface expression and cause congenital hyperinsulinism. Structurally diverse KATP inhibitors are known to act as pharmacochaperones to correct mutant channel expression, but the mechanism is unknown. Here, we compare cryoEM structures of a mammalian KATP channel bound to pharmacochaperones glibenclamide, repaglinide, and carbamazepine. We found all three drugs bind within a common pocket in SUR1. Further, we found the N-terminus of Kir6.2 inserted within the central cavity of the SUR1 ABC core, adjacent the drug binding pocket. The findings reveal a common mechanism by which diverse compounds stabilize the Kir6.2 N-terminus within SUR1's ABC core, allowing it to act as a firm 'handle' for the assembly of metastable mutant SUR1-Kir6.2 complexes.


Assuntos
Microscopia Crioeletrônica , Canais KATP/metabolismo , Canais KATP/ultraestrutura , Mamíferos/metabolismo , Preparações Farmacêuticas/metabolismo , Animais , Sítios de Ligação , Carbamatos/química , Carbamatos/metabolismo , Linhagem Celular , Cricetinae , Cisteína/genética , Glibureto/química , Glibureto/metabolismo , Humanos , Canais KATP/química , Modelos Moleculares , Mutação/genética , Preparações Farmacêuticas/química , Piperidinas/química , Piperidinas/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/química , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Ligação Proteica , Ratos
15.
Ecotoxicol Environ Saf ; 182: 109395, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31272022

RESUMO

Adding organic amendments to soil could modify the bioavailability of herbicides and lead to changes in the microbial community's activity and structure. The objective here was to study the dissipation and total mass balance of 14C-labeled prosulfocarb applied at two rates (4 and 10 mg kg-1) in unamended and green compost (GC)-amended soil. Soil dehydrogenase activity (DHA) and phospholipid fatty acid (PLFA) profile analysis were determined to evaluate the effect of herbicide residues on microbial community's activity and structure over the dissipation period. The dissipation rate of prosulfocarb decreased after soil amendment due to higher herbicide adsorption by the amended soil. The 50% dissipation time (DT50) increased 1.7 times in the unamended soil when the concentration of prosulfocarb increased 2.5 times. The mass balance results indicate that the sum of water and organic extractable fractions represented the highest amounts up to the dissipation of 50% 14C-prosulfocarb. The 14C-herbicide was then mainly mineralized (up to 11%-31%) or formed non-extractable residues (up to 35%-44%). The amount of 14C-prosulfocarb residues extracted with methanol was slightly higher in amended soils than in unamended ones. 14C-prosulfocarb mineralization was higher in unamended soils than in amended ones. The formation of non-extractable residues was continuous, and increased over time. Soil DHA decreased in the unamended soil and was maintained in the GC-amended soil at the end of the assay. The microbial structure was barely disturbed over the prosulfocarb degradation process, although it was clearly influenced by the application of GC. The results obtained reveal the influence organic amendment has on herbicide bioavailability to decrease its biodegradation and buffer its impact on the soil microbial structure.


Assuntos
Carbamatos/análise , Herbicidas/análise , Poluentes do Solo/análise , Adsorção , Biodegradação Ambiental , Carbamatos/química , Compostagem , Herbicidas/química , Microbiota , Solo/química , Microbiologia do Solo , Poluentes do Solo/química
16.
J Environ Sci Health B ; 54(11): 883-891, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31311415

RESUMO

The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in Ficopomatus enigmaticus as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of F. enigmaticus were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and in vitro response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from F. enigmaticus showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. In vitro data highlighted the presence of active forms of ChEs and CEs in F. enigmaticus that could potentially be inhibited by pesticides at environmentally relevant concentration.


Assuntos
Anelídeos/enzimologia , Inibidores da Colinesterase/toxicidade , Colinesterases/química , Neurotoxinas/toxicidade , Animais , Anelídeos/efeitos dos fármacos , Biomarcadores/química , Carbamatos/química , Carbaril/química , Carbaril/toxicidade , Carbofurano/química , Carbofurano/toxicidade , Hidrolases de Éster Carboxílico/antagonistas & inibidores , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Inibidores da Colinesterase/química , Colinesterases/metabolismo , Cinética , Metomil/química , Metomil/toxicidade , Neurotoxinas/química
17.
Eur J Pharm Biopharm ; 142: 165-178, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31226366

RESUMO

The present study focused upon the forced degradation behaviour of fosamprenavir (FPV), an antiretroviral drug. A total of six degradation products (DPs) were separated on a non-polar stationary phase by high performance liquid chromatography (HPLC). For the characterization, comprehensive mass fragmentation pathway of the drug was initially established using high resolution mass spectrometry (HRMS) and multi-stage tandem mass spectrometry (MSn) data. Subsequently, LC-HRMS and LC-MSn studies were carried out on the forced degraded samples containing the DPs. Five DPs were isolated and subjected to extensive 1D (1H, 13C, and DEPT-135 (distortionless enhancement by polarization)) and 2D (COSY (correlation spectroscopy), TOCSY (total correlation spectroscopy), HSQC (heteronuclear single quantum coherence) and HMBC (heteronuclear multiple bond correlation)) nuclear magnetic resonance (NMR) studies to ascertain their structures, while one degradation product was subjected to LC-NMR studies, as it could not be isolated. The collated information was helpful in characterization of all the DPs, and to delineate the degradation pathway of the drug. Additionally, physicochemical, as well as absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of the drug and its DPs were evaluated in silico by ADMET Predictor™ software.


Assuntos
Antirretrovirais/química , Carbamatos/química , Organofosfatos/química , Sulfonamidas/química , Cromatografia Líquida de Alta Pressão/métodos , Simulação por Computador , Estabilidade de Medicamentos , Espectroscopia de Ressonância Magnética/métodos , Software , Espectrometria de Massas em Tandem/métodos , Distribuição Tecidual/efeitos dos fármacos
18.
Methods Enzymol ; 622: 153-182, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31155051

RESUMO

The bioorthogonal reaction toolbox contains approximately two-dozen unique chemistries that permit selective tagging and probing of biomolecules. Over the past two decades, significant effort has been devoted to optimizing and discovering bioorthogonal reagents that are faster, fluorogenic, and orthogonal to the already existing bioorthogonal repertoire. Conversely, efforts to explore bioorthogonal reagents whose reactivity can be controlled in space and/or time are limited. The "activatable" bioorthogonal reagents that do exist are often unimodal, meaning that their reagent's activation method cannot be easily modified to enable activation with red-shifted wavelengths, enzymes, or metabolic-byproducts and ions like H2O2 or Fe3+. Here, we summarize the available activatable bioorthogonal reagents with a focus on our recent addition: modular caged cyclopropenes. We designed caged cyclopropenes to be unreactive to their bioorthogonal partner until they are activated through the removal of the cage by light, an enzyme, or another reaction partner. To accomplish this, their structure includes a nitrogen atom at the cyclopropene C3 position that is decorated with the desired caging group through a carbamate linkage. This 3-N cyclopropene system can allow control of cyclopropene reactivity using a multitude of already available photo- and enzyme-caging groups. Additionally, this cyclopropene scaffold can enable metabolic-byproduct or ion activation of bioorthogonal reactions.


Assuntos
Ciclopropanos/química , Animais , Biocatálise , Carbamatos/síntese química , Carbamatos/química , Técnicas de Química Sintética/métodos , Cromatografia Líquida de Alta Pressão/métodos , Ciclopropanos/síntese química , Humanos , Peróxido de Hidrogênio/química , Indicadores e Reagentes , Luz , Nitrogênio/química
19.
Chem Biol Interact ; 308: 392-395, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31175846

RESUMO

Carbamates are esters of substituted carbamic acids that react with acetylcholinesterase (AChE) by initially transferring the carbamoyl group to a serine residue in the enzyme active site accompanied by loss of the carbamate leaving group followed by hydrolysis of the carbamoyl enzyme. This hydrolysis, or decarbamoylation, is relatively slow, and half-lives of carbamoylated AChEs range from 4 min to more than 30 days. Therefore, carbamates are effective AChE inhibitors that have been developed as insecticides and as therapeutic agents. In this report, we review recent data showing that decarbamoylation rate constants are independent of the ester leaving group for a series of carbamic acid esters with the same carbamoyl group and that decarbamoylation rate constants decreased by 800-fold when the alkyl substituents on the carbamoyl group increased in size from N-monomethyl- to N,N-diethyl-. We also review data showing that solvent deuterium oxide isotope effects for decarbamoylation decreased from 2.8 for N-monomethylcarbamoyl AChE to 1.1 for N,N-diethylcarbamoyl AChE, indicating a shift in the rate-limiting step from general acid-base catalysis to a likely conformational change in the distorted active site in N,N-diethylcarbamoyl AChE. The nature of such a conformational change is suggested from X-ray crystal structures of AChE phosphorylated by paraoxon.


Assuntos
Acetilcolinesterase/metabolismo , Carbamatos/metabolismo , Acetilcolinesterase/química , Carbamatos/química , Domínio Catalítico , Cristalografia por Raios X , Cinética , Paraoxon/química , Paraoxon/metabolismo
20.
Eur J Med Chem ; 176: 187-194, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31103899

RESUMO

Inhibitors of the flaviviral serine proteases, which are crucial for the replication of dengue and West-Nile virus, have attracted much attention over the last years. A dibasic 4-guanidinobenzoate was previously reported as inhibitor of the dengue protease with potency in the low-micromolar range. In the present study, this lead structure was modified with the intent to explore structure-activity relationships and obtain compounds with increased drug-likeness. Substitutions of the guanidine moieties, the aromatic rings, and the ester with other functionalities were evaluated. All changes were accompanied by a loss of inhibition, indicating that the 4-guanidinobenzoate scaffold is an essential element of this compound class. Further experiments indicate that the target recognition of the compounds involves the reversible formation of a covalent adduct.


Assuntos
Amidas/química , Antivirais/química , Carbamatos/química , Ésteres/química , Inibidores da Tripsina/química , Amidas/síntese química , Antivirais/síntese química , Carbamatos/síntese química , Vírus da Dengue/efeitos dos fármacos , Vírus da Dengue/enzimologia , Estabilidade de Medicamentos , Ésteres/síntese química , Estrutura Molecular , Relação Estrutura-Atividade , Trombina/antagonistas & inibidores , Inibidores da Tripsina/síntese química , Proteínas não Estruturais Virais/antagonistas & inibidores , Vírus do Nilo Ocidental/efeitos dos fármacos , Vírus do Nilo Ocidental/enzimologia
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