The dark web scene has been drawing the attention of law enforcement agencies and researchers alike. To date, most of the published works on the dark web are based on data gained by passive observation. To gain a more contextualized perspective, a study was conducted in which three vendors were selected on the "Dream Market" dark web marketplace, from whom subsequently several new psychoactive substances (NPS) were ordered. All transactions were documented from the initial drug deal solicitation to the final qualitative analysis of all received samples. From the selected vendors, a total of nine NPS samples was obtained, all of which were analyzed by NMR, HRMS, LC-UV, and two also by x-ray diffraction. According to our analyses, four of the five substances offered under already known NPS names contained a different NPS. The selected vendors therefore either did not know about their product, or deliberately deceived the buyers. Furthermore, two of three obtained samples of purportedly novel NPS were identified as already documented substances sold under a different name. However, the third characterized substance sold as "MPF-47700" was a novel, yet uncharacterized, NPS. Finally, we received a single undeclared substance, later identified as 5F-ADB. In addition to chemical analysis of the nine obtained NPS samples, the methodology used also yielded contextual information about the accessibility of NPS on the dark web, the associated purchase process, and the modus operandi of three NPS vendors. Direct participation in dark web marketplaces seems to provide additional layers of information useful for forensic studies.
- MeSH
- hmotnostní spektrometrie MeSH
- internet MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- obchodování s drogami * MeSH
- odhalování abúzu drog MeSH
- psychotropní léky analýza zásobování a distribuce MeSH
- spektrofotometrie ultrafialová MeSH
- zakázané drogy analýza zásobování a distribuce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Alzheimer's disease (AD) is a multifactorial neurodegenerative condition of the central nervous system (CNS) that is currently treated by cholinesterase inhibitors and the N-methyl-d-aspartate receptor antagonist, memantine. Emerging evidence strongly supports the relevance of targeting butyrylcholinesterase (BuChE) in the more advanced stages of AD. Within this study, we have generated a pilot series of compounds (1-20) structurally inspired from belladine-type Amaryllidaceae alkaloids, namely carltonine A and B, and evaluated their acetylcholinesterase (AChE) and BuChE inhibition properties. Some of the compounds exhibited intriguing inhibition activity for human BuChE (hBuChE), with a preference for BuChE over AChE. Seven compounds were found to possess a hBuChE inhibition profile, with IC50 values below 1 μM. The most potent one, compound 6, showed nanomolar range activity with an IC50 value of 72 nM and an excellent selectivity pattern over AChE, reaching a selectivity index of almost 1400. Compound 6 was further studied by enzyme kinetics, along with in-silico techniques, to reveal the mode of inhibition. The prediction of CNS availability estimates that all the compounds in this survey can pass through the blood-brain barrier (BBB), as disclosed by the BBB score.
- MeSH
- acetylcholinesterasa chemie MeSH
- alkaloidy amarylkovitých chemie MeSH
- butyrylcholinesterasa chemie MeSH
- cholinesterasové inhibitory chemie farmakologie MeSH
- lidé MeSH
- nádorové buňky kultivované MeSH
- neuroblastom farmakoterapie patologie MeSH
- počítačová simulace MeSH
- proliferace buněk MeSH
- simulace molekulového dockingu * MeSH
- tyramin analogy a deriváty chemie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Fungal β-N-acetylhexosaminidases, though hydrolytic enzymes in vivo, are useful tools in the preparation of oligosaccharides of biological interest. The β-N-acetylhexosaminidase from Talaromyces flavus is remarkable in terms of its synthetic potential, broad substrate specificity, and tolerance to substrate modifications. It can be heterologously produced in Pichia pastoris in a high yield. The mutation of the Tyr470 residue to histidine greatly enhances its transglycosylation capability. The aim of this work was to identify the structural requirements of this model β-N-acetylhexosaminidase for its transglycosylation acceptors and formulate a structure-activity relationship study. Enzymatic reactions were performed using an activated glycosyl donor, 4-nitrophenyl N-acetyl-β-d-glucosaminide or 4-nitrophenyl N-acetyl-β-d-galactosaminide, and a panel of glycosyl acceptors of varying structural features (N-acetylglucosamine, glucose, N-acetylgalactosamine, galactose, N-acetylmuramic acid, and glucuronic acid). The transglycosylation products were isolated and structurally characterized. The C-2 N-acetamido group in the acceptor molecule was found to be essential for recognition by the enzyme. The presence of the C-2 hydroxyl moiety strongly hindered the normal course of transglycosylation, yielding unique non-reducing disaccharides in a low yield. Moreover, whereas the gluco-configuration at C-4 steered the glycosylation into the β(1-4) position, the galacto-acceptor afforded a β(1-6) glycosidic linkage. The Y470H mutant enzyme was tested with acceptors based on β-glycosides of uronic acid and N-acetylmuramic acid. With the latter acceptor, we were able to isolate and characterize one glycosylation product in a low yield. To our knowledge, this is the first example of enzymatic glycosylation of an N-acetylmuramic acid derivative. In order to explain these findings and predict enzyme behavior, a modeling study was accomplished that correlated with the acquired experimental data.
- MeSH
- beta-N-acetylhexosaminidasy chemie metabolismus MeSH
- glykosidy metabolismus MeSH
- glykosylace MeSH
- kinetika MeSH
- konformace proteinů MeSH
- molekulární modely MeSH
- oligosacharidy metabolismus MeSH
- substrátová specifita MeSH
- Talaromyces enzymologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
β-N-Acetylhexosaminidases (EC 3.2.1.52) are typical of their dual activity encompassing both N-acetylglucosamine and N-acetylgalactosamine substrates. Here we present the isolation and characterization of a selective β-N-acetylhexosaminidase from the fungal strain of Aspergillus versicolor. The enzyme was recombinantly expressed in Pichia pastoris KM71H in a high yield and purified in a single step using anion-exchange chromatography. Homologous molecular modeling of this enzyme identified crucial differences in the enzyme active site that may be responsible for its high selectivity for N-acetylglucosamine substrates compared to fungal β-N-acetylhexosaminidases from other sources. The enzyme was used in a sequential reaction together with a mutant β-N-acetylhexosaminidase from Talaromyces flavus with an enhanced synthetic capability, affording a bioactive disaccharide bearing an azido functional group. The azido function enabled an elegant multivalent presentation of this disaccharide on an aromatic carrier. The resulting model glycoconjugate is applicable as a selective ligand of galectin-3 - a biomedically attractive human lectin. These results highlight the importance of a general availability of robust and well-defined carbohydrate-active enzymes with tailored catalytic properties for biotechnological and biomedical applications.
- MeSH
- Aspergillus enzymologie MeSH
- beta-N-acetylhexosaminidasy chemie genetika izolace a purifikace metabolismus MeSH
- chromatografie iontoměničová MeSH
- disacharidy metabolismus MeSH
- exprese genu MeSH
- katalytická doména MeSH
- konformace proteinů MeSH
- molekulární modely MeSH
- Pichia genetika metabolismus MeSH
- rekombinantní proteiny chemie genetika izolace a purifikace metabolismus MeSH
- Talaromyces enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
