Inhibition of the human O-linked β-N-acetylglucosaminidase (hOGA, GH84) enzyme is pharmacologically relevant in several diseases such as neurodegenerative and cardiovascular disorders, type 2 diabetes, and cancer. Human lysosomal hexosaminidases (hHexA and hHexB, GH20) are mechanistically related enzymes; therefore, selective inhibition of these enzymes is crucial in terms of potential applications. In order to extend the structure-activity relationships of OGA inhibitors, a series of 2-acetamido-2-deoxy-d-glucono-1,5-lactone sulfonylhydrazones was prepared from d-glucosamine. The synthetic sequence involved condensation of N-acetyl-3,4,6-tri-O-acetyl-d-glucosamine with arenesulfonylhydrazines, followed by MnO2 oxidation to the corresponding glucono-1,5-lactone sulfonylhydrazones. Removal of the O-acetyl protecting groups by NH3/MeOH furnished the test compounds. Evaluation of these compounds by enzyme kinetic methods against hOGA and hHexB revealed potent nanomolar competitive inhibition of both enzymes, with no significant selectivity towards either. The most efficient inhibitor of hOGA was 2-acetamido-2-deoxy-d-glucono-1,5-lactone 1-naphthalenesulfonylhydrazone (5f, Ki = 27 nM). This compound had a Ki of 6.8 nM towards hHexB. To assess the binding mode of these inhibitors to hOGA, computational studies (Prime protein-ligand refinement and QM/MM optimizations) were performed, which suggested the binding preference of the glucono-1,5-lactone sulfonylhydrazones in an s-cis conformation for all test compounds.

• Klíčová slova
• Prime refinement, QM/MM optimization, glyconolactone sulfonylhydrazone, hHexB, hOGA, inhibitor,
• MeSH
• antigeny nádorové chemie   metabolismus   MeSH
• beta-hexosaminidasa, beta řetězec chemie   metabolismus   MeSH
• histonacetyltransferasy chemie   metabolismus   MeSH
• hyaluronoglukosaminidasa chemie   metabolismus   MeSH
• hydrazony chemická syntéza   chemie   farmakologie   MeSH
• inhibitory enzymů chemická syntéza   chemie   farmakologie   MeSH
• laktony chemie   MeSH
• lidé MeSH
• molekulární konformace MeSH
• molekulární modely MeSH
• oxidy chemie   MeSH
• sloučeniny manganu chemie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny nádorové MeSH
• beta-hexosaminidasa, beta řetězec MeSH
• HEXB protein, human MeSH Prohlížeč
• histonacetyltransferasy MeSH
• hyaluronoglukosaminidasa MeSH
• hydrazony MeSH
• inhibitory enzymů MeSH
• laktony MeSH
• manganese dioxide MeSH Prohlížeč
• OGA protein, human MeSH Prohlížeč
• oxidy MeSH
• sloučeniny manganu MeSH

Influenza neuraminidase is responsible for the escape of new viral particles from the infected cell surface. Several neuraminidase inhibitors are used clinically to treat patients or stockpiled for emergencies. However, the increasing development of viral resistance against approved inhibitors has underscored the need for the development of new antivirals effective against resistant influenza strains. A facile, sensitive, and inexpensive screening method would help achieve this goal. Recently, we described a multiwell plate-based DNA-linked inhibitor antibody assay (DIANA). This highly sensitive method can quantify femtomolar concentrations of enzymes. DIANA also has been applied to high-throughput enzyme inhibitor screening, allowing the evaluation of inhibition constants from a single inhibitor concentration. Here, we report the design, synthesis, and structural characterization of a tamiphosphor derivative linked to a reporter DNA oligonucleotide for the development of a DIANA-type assay to screen potential influenza neuraminidase inhibitors. The neuraminidase is first captured by an immobilized antibody, and the test compound competes for binding to the enzyme with the oligo-linked detection probe, which is then quantified by qPCR. We validated this novel assay by comparing it with the standard fluorometric assay and demonstrated its usefulness for sensitive neuraminidase detection as well as high-throughput screening of potential new neuraminidase inhibitors.

• Klíčová slova
• DIANA, assay, crystallography, influenza neuraminidase,
• MeSH
• antivirové látky chemie   farmakologie   MeSH
• chřipka lidská farmakoterapie   enzymologie   virologie   MeSH
• DNA chemie   MeSH
• inhibitory enzymů chemie   farmakologie   MeSH
• kyseliny fosforité chemie   MeSH
• lidé MeSH
• neuraminidasa antagonisté a inhibitory   metabolismus   MeSH
• oseltamivir analogy a deriváty   chemie   MeSH
• preklinické hodnocení léčiv metody   MeSH
• reprodukovatelnost výsledků MeSH
• virové proteiny antagonisté a inhibitory   metabolismus   MeSH
• virus chřipky A účinky léků   enzymologie   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antivirové látky MeSH
• DNA MeSH
• inhibitory enzymů MeSH
• kyseliny fosforité MeSH
• neuraminidasa MeSH
• oseltamivir MeSH
• tamiphosphor MeSH Prohlížeč
• virové proteiny MeSH

Neuraminidase is the main target for current influenza drugs. Reduced susceptibility to oseltamivir, the most widely prescribed neuraminidase inhibitor, has been repeatedly reported. The resistance substitutions I223V and S247N, alone or in combination with the major oseltamivir-resistance mutation H275Y, have been observed in 2009 pandemic H1N1 viruses. We overexpressed and purified the ectodomain of wild-type neuraminidase from the A/California/07/2009 (H1N1) influenza virus, as well as variants containing H275Y, I223V, and S247N single mutations and H275Y/I223V and H275Y/S247N double mutations. We performed enzymological and thermodynamic analyses and structurally examined the resistance mechanism. Our results reveal that the I223V or S247N substitution alone confers only a moderate reduction in oseltamivir affinity. In contrast, the major oseltamivir resistance mutation H275Y causes a significant decrease in the enzyme’s ability to bind this drug. Combination of H275Y with an I223V or S247N mutation results in extreme impairment of oseltamivir’s inhibition potency. Our structural analyses revealed that the H275Y substitution has a major effect on the oseltamivir binding pose within the active site while the influence of other studied mutations is much less prominent. Our crystal structures also helped explain the augmenting effect on resistance of combining H275Y with both substitutions.

• Klíčová slova
• crystal structure, influenza neuraminidase, isothermal titration calorimetry, oseltamivir, resistance,
• MeSH
• antivirové látky farmakologie   MeSH
• chřipka lidská virologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• kalorimetrie MeSH
• kinetika MeSH
• krystalizace MeSH
• lidé MeSH
• missense mutace MeSH
• neuraminidasa chemie   genetika   MeSH
• oseltamivir farmakologie   MeSH
• replikace viru MeSH
• substituce aminokyselin MeSH
• termodynamika MeSH
• virová léková rezistence genetika   MeSH
• virové proteiny chemie   genetika   MeSH
• virus chřipky A, podtyp H1N1 účinky léků   enzymologie   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antivirové látky MeSH
• inhibitory enzymů MeSH
• neuraminidasa MeSH
• oseltamivir MeSH
• virové proteiny MeSH

Caffeine is an alkaloid with a stimulant effect in the body. It can interfere in transmissions based on acetylcholine, epinephrine, norepinephrine, serotonin, dopamine and glutamate. Clinical studies indicate that it can be involved in the slowing of Alzheimer disease pathology and some other effects. The effects are not well understood. In the present work, we focused on the question whether caffeine can inhibit acetylcholinesterase (AChE) and/or, butyrylcholinesterase (BChE), the two enzymes participating in cholinergic neurotransmission. A standard Ellman test with human AChE and BChE was done for altering concentrations of caffeine. The test was supported by an in silico examination as well. Donepezil and tacrine were used as standards. In compliance with Dixon's plot, caffeine was proved to be a non-competitive inhibitor of AChE and BChE. However, inhibition of BChE was quite weak, as the inhibition constant, Ki, was 13.9 ± 7.4 mol/L. Inhibition of AChE was more relevant, as Ki was found to be 175 ± 9 µmol/L. The predicted free energy of binding was -6.7 kcal/mol. The proposed binding orientation of caffeine can interact with Trp86, and it can be stabilize by Tyr337 in comparison to the smaller Ala328 in the case of human BChE; thus, it can explain the lower binding affinity of caffeine for BChE with reference to AChE. The biological relevance of the findings is discussed.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory farmakologie   MeSH
• kofein farmakologie   MeSH
• lidé MeSH
• molekulární modely MeSH
• počítačová simulace MeSH
• rekombinantní proteiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcholinesterasa MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• kofein MeSH
• rekombinantní proteiny MeSH

OBJECTIVE: The aim of the present study was to predict the drug interaction potential of memantine by elucidation of its inhibitory effects on cytochrome P450 enzymes using pooled human liver microsomes (HLM) and recombinant P450s. METHODS: The inhibitory potency of memantine on CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 activities was examined with specific probe drugs in HLM and recombinant P450s. The in vivo drug interactions of memantine were predicted in vitro using the [ I]/([ I] + KI) values. RESULTS: In HLM, memantine inhibited CYP2B6 and CYP2D6 activities, with KI (IC50) values of 76.7 (279.7) and 94.9 (368.7) microM, respectively. Both inhibitions were competitive. In addition, cDNA-expressed P450s were used to confirm these results. Memantine strongly inhibited recombinant CYP2B6 activity with IC50 ( KI) value of 1.12 (0.51) microM and activity of recombinant CYP2D6 with IC50 (KI) value of 242.4 (84.4) microM. With concentrations up to 1,000 microM, memantine showed no appreciable effect on CYP1A2, CYP2E1, CYP2C9, or CYP3A4 activities and a slight decrease of CYP2A6 and CYP2C19 activities. Based on [ I]/([ I] + KI) values calculated using peak total plasma concentration (or enzyme-available concentration in the liver) of memantine and the KI obtained in HLM, 1.3 (13.5), and 1.0% (11.2%), inhibition of the clearance of CYP2B6 and CYP2D6 substrates could be expected, respectively. Nevertheless, when considering KI values obtained from cDNA-expressed CYP2B6, as generally recommended, even 66.2% (95.9%) decrease in metabolism of coadministered CYP2B6 substrates could be anticipated. CONCLUSION: Memantine exerts selective inhibition of CYP2B6 activity at clinically relevant concentrations, suggesting the potential for clinically significant drug interactions. Inhibition of other CYPs during memantine therapy is unlikely. Moreover, memantine represents a new, potent, selective inhibitor of recombinant CYP2B6, which may prove useful for screening purposes during early phases of in vitro drug metabolism studies with new chemical entities.

• MeSH
• antiparkinsonika aplikace a dávkování   farmakologie   MeSH
• inhibiční koncentrace 50 MeSH
• inhibitory cytochromu P450 MeSH
• inhibitory enzymů aplikace a dávkování   farmakologie   MeSH
• jaterní mikrozomy účinky léků   MeSH
• lékové interakce MeSH
• lidé MeSH
• memantin aplikace a dávkování   farmakologie   MeSH
• systém (enzymů) cytochromů P-450 účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiparkinsonika MeSH
• inhibitory cytochromu P450 MeSH
• inhibitory enzymů MeSH
• memantin MeSH
• systém (enzymů) cytochromů P-450 MeSH

Respiration of yeasts Saccharomyces cerevisiae, Rhodotorula glutinis, Endomyces magnusii, and Candida utilis, and of bacteria Escherichia coli and Bacillus megaterium, anaerobic production of CO2 by S. cerevisiae, active transport of quinovose by R. glutinis and of L-proline and L-leucine by S. cerevisiae were highly dependent on cell suspension density. Respiration of S. cerevisiae in the presence of glucose decreased in a biphasic fashion from 140 to 40 nmol O2 per mg dry solid per min as suspension density increased from 0.01 to 2 mg/mL. Higher partial pressures of oxygen further enhanced the trend. The active transports were affected monophasically in the maximum rate of uptake which was as much as ten times greater at low than at high suspension densities. A component of the external medium is suspected to cause the decrease of metabolic functions at higher cell densities, acting as a noncompetitive inhibitor. The component was present and mutually active in suspensions of the various yeasts as well as of bacteria. Its properties and results of model experiments suggest it to be dissolved carbon dioxide.

• MeSH
• aktivní transport MeSH
• anaerobióza MeSH
• Bacillus megaterium metabolismus   MeSH
• bakteriologické techniky MeSH
• buněčná membrána metabolismus   MeSH
• Candida metabolismus   MeSH
• Escherichia coli metabolismus   MeSH
• houby metabolismus   MeSH
• kinetika MeSH
• oxid uhličitý metabolismus   MeSH
• Rhodotorula metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• Saccharomycetales metabolismus   MeSH
• spotřeba kyslíku MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• oxid uhličitý MeSH

The activities of glucose-6-phosphate dehydrogenase (GPD) and 6-phosphogluconate dehydrogenase (decarboxylating) (PGD) in Saccharomyces cerevisiae were found to change by a factor similar to the reported changes in the rate of the pentose phosphate pathway between cells grown in minimal medium and in rich medium. It is suggested that the rate of this pathway is regulated not only by the activity of GPD, a well-known key enzyme, but also by PGD. These two enzymes seem to function in a coordinated fashion.

• MeSH
• aminokyseliny farmakologie   MeSH
• fosfoglukonátdehydrogenasa metabolismus   MeSH
• glukosa-6-fosfátdehydrogenasa metabolismus   MeSH
• kinetika MeSH
• kultivační média MeSH
• NADP farmakologie   MeSH
• pentosafosfáty metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH
• fosfoglukonátdehydrogenasa MeSH
• glukosa-6-fosfátdehydrogenasa MeSH
• kultivační média MeSH
• NADP MeSH
• pentosafosfáty MeSH

• MeSH
• azidy farmakologie   MeSH
• Bacteria metabolismus   MeSH
• dusičnany metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• kultivační média MeSH
• kyanidy farmakologie   MeSH
• spotřeba kyslíku MeSH
• teplota MeSH
• thiosírany metabolismus   MeSH
• transport elektronů * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• azidy MeSH
• dusičnany MeSH
• kultivační média MeSH
• kyanidy MeSH
• thiosírany MeSH