TY - JOUR AU - Bokros, Attila AU - Bánfi, Annamária AU - Kupihár, Zoltán AU - Kele, Zoltán AU - Tóthné Illyés, Tünde Zita AU - Szolomájer, János AU - Kovács, Lajos TI - Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides JF - MOLECULES J2 - MOLECULES VL - 17 PY - 2012 IS - 7 SP - 8351 EP - 8358 PG - 8 SN - 1420-3049 DO - 10.3390/molecules17078351 UR - https://m2.mtmt.hu/api/publication/2015022 ID - 2015022 AB - Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+ etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds. LA - English DB - MTMT ER - TY - JOUR AU - Fekete, Anikó AU - Borbás, Anikó AU - Gyémánt, Gyöngyi AU - Kandra, Lili AU - Fazekas, Erika AU - Ramasubbu, N AU - Antus, Sándor TI - Synthesis of beta-(1->6)-linked N-acetyl-D-glucosamine oligosaccharide substrates and their hydrolysis by Dispersin B JF - CARBOHYDRATE RESEARCH J2 - CARBOHYD RES VL - 346 PY - 2011 IS - 12 SP - 1445 EP - 1453 PG - 9 SN - 0008-6215 DO - 10.1016/j.carres.2011.03.029 UR - https://m2.mtmt.hu/api/publication/1629372 ID - 1629372 N1 - Funding Agency and Grant Number: Hungarian Scientific Research FundOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [PD73064]; European Social FundEuropean Social Fund (ESF); European Regional Development FundEuropean Commission; [TAMOP 4.2.1./B-09/1/KONV-2010-0007]; NATIONAL INSTITUTE OF DENTAL &CRANIOFACIAL RESEARCHUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Dental & Craniofacial Research (NIDCR) [R01DE016291] Funding Source: NIH RePORTER Funding text: This work was supported by the Hungarian Scientific Research Fund (Project No. PD73064) and by the TAMOP 4.2.1./B-09/1/KONV-2010-0007 project. The project is implemented through the New Hungary Development Plan, co-financed by the European Social Fund and the European Regional Development Fund. AB - Dispersin B (DspB) from Aggregatibacter actinomycetemcomitans is a p-hexosaminidase exhibiting biofilm detachment activity. A series of beta-(1 -> 6)-linked N-acetyl-D-glucosamine thiophenyl glycosides with degree of polymerisation (DP) of 2, 3, 4 and 5 were synthesized, and substrate specificity of DspB was studied on the obtained oligosaccharides. For oligomer synthesis a 1+2, 2+2, 1+4 coupling strategy was applied, using bromo-sugars as glycosyl donors. The formation of 1,2-trans interglycosidic bond has been ensured by 2-phtalimido protecting group: chloroacetyl group was installed to mask temporarily the 6-hydroxyl and acetate esters were applied as permanent protecting groups. Enzymatic studies revealed that DP of the GlcNAc oligomers strongly affected the hydrolysis rate, and the hydrolytic activity of DspB on the tetramer and pentamer have been found to be approximately 10-fold higher than that of the dimer. This fact indicates that four units are required for a strong binding at the active centre of DspB. The role of aromatic amino acids W237, Y187 and Y278 in substrate specificity and catalysis was also examined using mutant enzymes. (C) 2011 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Bokor, Éva TI - Heterociklusos glükózszármazékok, mint lehetséges antidiabetikumok JF - MAGYAR KÉMIKUSOK LAPJA J2 - MAGY KEM LAP VL - 65 PY - 2010 IS - 3 SP - 77 EP - 78 PG - 2 SN - 0025-0163 UR - https://m2.mtmt.hu/api/publication/1779925 ID - 1779925 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Chrysina, E D AU - Bokor, Éva AU - Alexacou, K-M AU - Charavgi, M-D AU - Oikonomakos, G N AU - Zographos, S E AU - Leonidas, D D AU - Oikonomakos, N G AU - Somsák, László TI - Amide-1,2,3-triazole bioisosterism: the glycogen phosphorylase case JF - TETRAHEDRON-ASYMMETRY J2 - TETRAHEDRON ASYMMETR VL - 20 PY - 2009 SP - 733 EP - 740 PG - 8 SN - 0957-4166 DO - 10.1016/j.tetasy.2009.03.021 UR - https://m2.mtmt.hu/api/publication/1779815 ID - 1779815 N1 - Megjegyzés-22018892 Z9: 11 WC: Chemistry, Inorganic & Nuclear; Chemistry, Organic; Chemistry, Physical Megjegyzés-22034691 FU: EU Marie Curie Early Stage Training (EST) [MEST-CT-020575]; Marie Curie : Host Fellowships for the Transfer of Knowledge (ToK) : [MTKD-CT-2006-042776]; Hellenic General Secretariat for Research and : Technology (GSRT) ; Ministry of Development ; EMBL-Hamburg outstation : under FP6 'Structuring the European Research Area Programme' : [RII3/CT/2004/5060008]; SRS Daresbury Laboratory [IHPP : HPRI-CT-1999-00012]; Hungarian Scientific Research Fund [OTKA 61336, : 68578] FX: This work was supported by the EU Marie Curie Early Stage Training : (EST) Contract No. MEST-CT-020575; a Marie Curie Host Fellowships for : the Transfer of Knowledge (ToK) contract no MTKD-CT-2006-042776; the : Hellenic General Secretariat for Research and Technology (GSRT), : Ministry of Development, through the program 'Excellence in Research : Institutes (2nd round)' to N.G.O.; the EMBL-Hamburg outstation under : FP6 'Structuring the European Research Area Programme' Contract No. : RII3/CT/2004/5060008 and SRS Daresbury Laboratory (contract IHPP : HPRI-CT-1999-00012). We are grateful to the staff scientists at : EMBL-Hamburg outstation and SRS Daresbury Laboratory for their help : during X-ray data collection. Synthetic work in Debrecen was supported : by the Hungarian Scientific Research Fund (OTKA 61336 and 68578). LA - English DB - MTMT ER - TY - JOUR AU - Somsák, László AU - Felföldi, N AU - Kónya, B AU - Hüse, Cs AU - Telepó, K AU - Bokor, Éva AU - Czifrák, Katalin TI - Assessment of synthetic methods for the preparation of N'-b-D-glucopyranosyl-N-substituted ureas, thioureas and related compounds JF - CARBOHYDRATE RESEARCH J2 - CARBOHYD RES VL - 343 PY - 2008 SP - 2083 EP - 2093 PG - 11 SN - 0008-6215 DO - 10.1016/j.carres.2008.01.045 UR - https://m2.mtmt.hu/api/publication/1779732 ID - 1779732 LA - English DB - MTMT ER - TY - JOUR AU - Farkas, Etelka AU - Megyeri, K AU - Somsák, László AU - Kovács, Lajos TI - Interaction between Mo(VI) and siderophore models in aqueous solution JF - JOURNAL OF INORGANIC BIOCHEMISTRY J2 - J INORG BIOCHEM VL - 70 PY - 1998 IS - 1 SP - 41 EP - 47 PG - 7 SN - 0162-0134 DO - 10.1016/S0162-0134(98)00011-7 UR - https://m2.mtmt.hu/api/publication/1391828 ID - 1391828 AB - A series of dihydroxamic acids (HORNOC-(CH2)(n)-CONROH, where if R = H - then n = 2, 5-7 and if R = CH3- then n = 4, 5) and two new dihydroxamate-based siderophore models, hexanedioic acid bis (3-hydroxycarbamoyl-methyl)amide (DhaI) and hexanedioic acid bis(3-hydroxycarbamoyl-propyl)amide (DhaII) have been characterized in terms of chelating properties toward molybdenum(VI). For comparison, the molybdenum(VI)-acetohydroxamic acid (Aha) and molybdenum(VI)-aminohydroxamic acid systems have also been studied. Potentiometric and spectrophotometric studies at ionic strength of 0.2 mol/dm(3) (KCl) and at 25 degrees C have been performed and the equilibrium constants have been determined. It has been found, that of the dihydroxamic acids, only the DhaI and DhaII form water soluble complexes with molybdenum(VI). Polynuclear complexes most probably precipitate with the other dihydroxamic acids. Complexes are formed up to ca. the neutral pH in all systems. Above this pH MoO42- and the free ligands exist. Although, very stable complexes are formed especially with DhaII, none of the studied ligands form a single bis(hydroxamato)dioxomolybdenum(VI) species. Mo no(hydroxamato) trioxomolybdenum(VI) species are also formed, containing the uncoordinated moiety of the DhaI or DhaII in its protonated form. Out of aminohydroxamic acids, the beta-alaninehydroxamic acid (beta-Alaha) shows "Aha-like" coordination properties as the glutamic acid-gamma-hydroxamic acid (Glu-gamma-ha) does. The small differences with this latter ligand are possibly due to weak coordination of the carboxylate which makes the mono(hydroxamato)trioxomolybdenum(VI) species more stable and the uncoordinated carboxylates in bis(hydroxamato) dioxomolybdenum(VI) can protonate below pH 3. The tridentate coordination mode of aspartic acid-P-hydroxamic acid (Asp-P-ha) via the hydroxamate and carboxylate oxygens results in the formation of a dinuclear complex, [Mo2O5(LH)(2)](2-) in addition to [MoO3(LH)](-) (the protons are on the amino groups) in the pi-I-range 2.5-7.0. (C) 1998 Elsevier Science Inc. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Lajos AU - Herczegh, Pál AU - Batta, Gyula AU - I, Farkas TI - Thiazole c-nucleosides .3. Synthesis of pyranose analogs of tiazofurin JF - TETRAHEDRON J2 - TETRAHEDRON VL - 47 PY - 1991 IS - 29 SP - 5539 EP - 5548 PG - 10 SN - 0040-4020 DO - 10.1016/S0040-4020(01)80985-6 UR - https://m2.mtmt.hu/api/publication/1163352 ID - 1163352 N1 - : FN Thomson Reuters Web of Knowledge Z9: 22 WC: Chemistry, Organic AB - A large-scale synthesis of 3,4,5-tri-0-acetyl-2,6-anhydro-L-mannono-and-D-gulonothioamides (5, 6) has been achieved from the corresponding nitriles. The Hantzsch reaction of (5) or (6) with ethyl bromopyruvate afforded the expected thiazoles (7.8) only in a low yield along with furan derivatives (9-11), the formation of which is rationalized by an acid-catalysed rearrangement-elimination process. The some Hantzsch reaction in the presence of barium carbonate yielded hydroxythiazolines (16,17). Attempted dehydration of (16) or (17) with trifluoroacetic anhydride or trifluoroacetic anhydride/pyridine resulted in the formation of pent-1′-enopyranosylthiazoles (18-20). Deprotected thioamides (24,25) furnished with ethyl bromopyruvate thiazoles (27,28). The obtained thiazole esters (7,8, 18-20. 27,28) were transformed into new tiazofurin analogues (12, 13, 21- 23). New tiazofurin analogues (1-5) have been synthesized starting from the corresponding thioamides. LA - English DB - MTMT ER - TY - JOUR AU - Kovács, Lajos AU - Herczegh, Pál AU - Batta, Gyula AU - I, Farkas TI - 2 acyclic analogs of 2-beta-d-ribofuranosylthiazole-4-carboxamide (Tiazofurin) JF - HETEROCYCLES J2 - HETEROCYCLES VL - 26 PY - 1987 IS - 4 SP - 947 EP - 960 PG - 14 SN - 0385-5414 UR - https://m2.mtmt.hu/api/publication/1162088 ID - 1162088 LA - English DB - MTMT ER -