imidazole OR C029899 Dotaz Zobrazit nápovědu
Plant cytosolic aldehyde dehydrogenases from family 2 (ALDH2s, EC 1.2.1.3) are non-specific enzymes and participate for example in the metabolism of acetaldehyde or biosynthesis of phenylpropanoids. Plant aminoaldehyde dehydrogenases (AMADHs, ALDH10 family, EC 1.2.1.19) are broadly specific and play an important role in polyamine degradation or production of osmoprotectants. We have tested imidazole and pyrazole carbaldehydes and their alkyl-, allyl-, benzyl-, phenyl-, pyrimidinyl- or thienyl-derivatives as possible substrates of plant ALDH2 and ALDH10 enzymes. Imidazole represents a building block of histidine, histamine as well as certain alkaloids. It also appears in synthetic pharmaceuticals such as imidazole antifungals. Biological compounds containing pyrazole are rare (e.g. pyrazole-1-alanine and pyrazofurin antibiotics) but the ring is often found as a constituent of many synthetic drugs and pesticides. The aim was to evaluate whether aldehyde compounds based on azole heterocycles are oxidized by the enzymes, which would further support their expected role as detoxifying aldehyde scavengers. The analyzed imidazole and pyrazole carbaldehydes were only slowly converted by ALDH10s but well oxidized by cytosolic maize ALDH2 isoforms (particularly by ALDH2C1). In the latter case, the respective Km values were in the range of 10-2000 μmol l-1; the kcat values appeared mostly between 0.1 and 1.0 s-1. The carbaldehyde group at the position 4 of imidazole was oxidized faster than that at the position 2. Such a difference was not observed for pyrazole carbaldehydes. Aldehydes with an aromatic substituent on their heterocyclic ring were oxidized faster than those with an aliphatic substituent. The most efficient of the tested substrates were comparable to benzaldehyde and p-anisaldehyde known as the best aromatic aldehyde substrates of plant cytosolic ALDH2s in vitro.
- Klíčová slova
- Aldehyde dehydrogenase, Aminoaldehyde dehydrogenase, Imidazole, Isoenzyme, Pyrazole, Substrate,
- MeSH
- aldehyddehydrogenasa metabolismus MeSH
- aldehydy chemie metabolismus MeSH
- hrách setý enzymologie MeSH
- imidazoly chemie metabolismus MeSH
- kukuřice setá enzymologie MeSH
- molekulární struktura MeSH
- oxidace-redukce MeSH
- pyrazoly chemie metabolismus MeSH
- Solanum lycopersicum enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aldehyddehydrogenasa MeSH
- aldehydy MeSH
- imidazole MeSH Prohlížeč
- imidazoly MeSH
- pyrazole MeSH Prohlížeč
- pyrazoly MeSH
Hydration of neutral and cationic imidazole is studied by means of ab initio and molecular dynamics calculations, and by photoelectron spectroscopy of the neutral species in a liquid microjet. The calculations show the importance of long range solvent polarization and of the difference between the structure of water molecules in the first shell around the neutral vs cationic species for determining vertical and adiabatic ionization potentials. The vertical ionization potential of neutral imidazole of 8.06 eV calculated using a nonequilibrium polarizable continuum model agrees well with the value of 8.26 eV obtained experimentally for an aqueous solution at pH 10.6.
Twelve new imidazole-based potential bi- and tridentate ligands were synthesized and characterized. Whereas in the first series the alpha-amino acid and imidazole moieties were linked by an amino bond, in the second series the tridentate ligands, containing two imidazole groups, were separated by an amide bond. The first series was obtained by the reductive amination of 2-phenylimidazole-4-carboxaldehyde with alpha-amino acid esters. The tridentate ligands were prepared from 2-phenylimidazole-4-carboxylic acid and chiral amines. In the Henry reaction, the amines were revealed as a more reactive species than the less nucleophilic amides, however the enantiomeric excesses were generally poor.
- MeSH
- chemické modely MeSH
- imidazoly chemie MeSH
- katalýza MeSH
- ligandy * MeSH
- molekulární struktura MeSH
- sloučeniny dusíku chemie MeSH
- stereoizomerie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- imidazole MeSH Prohlížeč
- imidazoly MeSH
- ligandy * MeSH
- sloučeniny dusíku MeSH
The photodissociation of imidazole in hydrogen bonded clusters has been studied at photodissociation wavelengths 243 and 193 nm. Imidazole clusters of different mean cluster sizes n approximately 3 and 6 have been produced in expansions with He and Ar carrier gases, and the mean cluster sizes were determined by mass spectrometric and crossed beam scattering experiments. Simultaneously, the (C(3)N(2)H(4))(n) clusters were studied by ab initio calculations for n up to 4 molecules, confirming the hydrogen bond N-H...N motif in the clusters. The measured H-fragment kinetic energy distribution spectra exhibit a bimodal character similar to the KEDs found for the bare molecule. (1) At 243 nm the fast H-atoms originate from the direct dissociation process on the repulsive pi sigma* state, and the slow component results from the dynamics populating the vibrationally hot ground state via an S(1)/S(0) conical intersection. In the clusters the contribution of the slow component increases with the cluster size. The slow component is also dominant at the shorter wavelength of 193 nm, where the dynamics starts with the excitation of pi pi* state. It is shown that the slow component in our experiment is a product of subsequent two-photon absorption. We have proposed different mechanisms how the observed enhanced internal conversion can be rationalized. The increased stability with respect to the H-fragment dissociation in clusters can be caused either by hydrogen transfer in the N-H...N bond or by closing the pi sigma* dissociation channel as in the case of pyrrole clusters.
- MeSH
- fotochemické procesy * MeSH
- hmotnostní spektrometrie MeSH
- imidazoly chemie MeSH
- kinetika MeSH
- kvantová teorie MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- termodynamika MeSH
- vodíková vazba MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- imidazole MeSH Prohlížeč
- imidazoly MeSH
Homological series of 14 achiral derivates and series of five chiral derivates of imidazole were tested in vitro as inhibitors of hydrolysis of acetylcholine using enzyme preparation of acetylcholinesterase from electric eel. The batch stirred reactor at 25 degrees C, pH 8 (phosphate buffer), ionic strength 0.11 M and catalytic activity of the enzyme preparation 0.14 U ml(-1) of the reaction mixture were used. The temporal dependences of actual concentrations of acetylcholine, choline and acetic acid were determined by an original HPLC method. For all used inhibitors, these time dependences conform with the probability of more than 90% to the model of competitive irreversible inhibition. All kinetic constants including k(3) defining the rate of inhibition (0.38-5.3M(-1)s(-1)) and qualified estimation of the absolute acetylcholinesterase concentration in the reaction mixture (40-110 nM) were determined.
- MeSH
- acetylcholinesterasa chemie MeSH
- aktivace enzymů MeSH
- cholinesterasové inhibitory chemie MeSH
- Electrophorus metabolismus MeSH
- imidazoly chemie MeSH
- stabilita enzymů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- acetylcholinesterasa MeSH
- cholinesterasové inhibitory MeSH
- imidazole MeSH Prohlížeč
- imidazoly MeSH
A total of 84 strains of the dermatophyte Trichophyton mentagrophytes were studied for their sensitivity to ketoconazole, miconazole, and clotrimazole. Minimal inhibitory concentration was used for determination of sensitivity. Variability in the sensitivity of strains to the tested imidazole drugs ranged within one to two orders (10(-2)-10(0) micrograms/ml). By means of UV radiation ketoconazole-resistant mutants were prepared: their frequency was 1.3 x 10(-7) mutants per spore and nucleus. A repeated exposition to the mutagen lead to increased resistance. Correlation was also studied between inhibitory effect of ketoconazole on mycelial growth and that on ergosterol biosynthesis but no significant results were obtained.
Research activities in the field of imidazole-derived push-pull systems featuring intramolecular charge transfer (ICT) are reviewed. Design, synthetic pathways, linear and nonlinear optical properties, electrochemistry, structure-property relationships, and the prospective application of such D-π-A organic materials are described. This review focuses on Y-shaped imidazoles, bi- and diimidazoles, benzimidazoles, bis(benzimidazoles), imidazole-4,5-dicarbonitriles, and imidazole-derived chromophores chemically bound to a polymer chain.
- Klíčová slova
- charge transfer, chromophore, conjugation, donor–acceptor system, imidazole,
- Publikační typ
- časopisecké články MeSH
Five optically active imidazole derivatives have been synthesized via a facile 4-step reaction sequence starting from commercially available and inexpensive N-Cbz amino acids. While microwave assisted condensation was unsuccessful, the condensation of the corresponding alpha-bromoketones with formamidine acetate in liquid ammonia was revealed to be a useful method for the synthesis of such imidazole derivatives. The derivatives thus prepared are structurally-related to histamine.
2D layered materials, including metal-di-chalcogenides and transition metal layered double hydroxides, among others, are intensively studied because of new properties that emerge from their 2D confinement, which are attractive for advanced applications. Herein, 2D cobalt ion (Co2+) and benzimidazole (bIm) based zeolite-imidazole framework nanosheets, ZIF-9(III), are reported as exceptionally efficient electrocatalysts for the oxygen evolution reaction (OER). Specifically, liquid-phase ultrasonication is applied to exfoliate a [Co4(bIm)16] zeolite-imidazole framework (ZIF), named as ZIF-9(III) phase, into nanoscale sheets. ZIF-9(III) is selectively prepared through simple mechanical grinding of cobalt nitrate and benzimidazole in the presence of a small amount of ethanol. The resultant exfoliated nanosheets exhibit significantly higher OER activity in alkaline conditions than the corresponding bulk phases ZIF-9 and ZIF-9(III). The electrochemical and physicochemical characterization data support the assignment of the OER activity of the exfoliated nanosheet derived material to nitrogen coordinated cobalt oxyhydroxide N4CoOOH sites, following a mechanism known for Co-porphyrin and related systems. Thus, exfoliated 2D nanosheets hold promise as potential alternatives to commercial noble metal electrocatalysts for the OER.
- Klíčová slova
- 2D materials, electrocatalysis, liquid‐phase exfoliation, mechanochemical synthesis, oxygen evolution, zeolite imidazole frameworks (ZIFs),
- Publikační typ
- časopisecké články MeSH
- Klíčová slova
- IMIDAZOLES *,
- MeSH
- imidazoly * MeSH
- sympatolytika * MeSH
- sympatomimetika * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- imidazole MeSH Prohlížeč
- imidazoly * MeSH
- sympatolytika * MeSH
- sympatomimetika * MeSH
