TY - JOUR AU - Sándor, Balázs AU - Hőgyéné Grenács, Ágnes Judit AU - Nagy, Lajos AU - Hollóczki, Oldamur AU - Várnagy, Katalin TI - Complex Formation and Hydrolytic Processes of Protected Peptides Containing the –SXH– Motif in the Presence of Nickel(II) Ion JF - CHEMBIOCHEM J2 - CHEMBIOCHEM VL - & PY - 2024 SN - 1439-4227 DO - 10.1002/cbic.202400475 UR - https://m2.mtmt.hu/api/publication/35134053 ID - 35134053 AB - Interactions between metal ions and proteins are considered reversible, such as the coordination of a metal ion to a protein or enzyme, but irreversible processes like the oxidative reactions, aggregation or hydrolytic processes may occur. In the presence of Ni(II)‐ions selective hydrolysis of the peptides containing the –SXH– or –TXH– motif was observed. Since the side chain of histidine serves as the metal ion binding site for many native proteins, and very often histidine is present in a –SXH– or –TXH– sequence, to study the complex formation and hydrolytic processes in presence of nickel(II) ion four peptides were synthesised: Ac‐SKHM‐NH2, A3SSH‐NH2, A4SSH‐NH2, AAAeKSH‐NH2. The Ni(II)‐induced hydrolysis of Ac‐SKHM‐NH2 peptide occurs rapidly in alkaline medium already at room temperature. In two peptides containing –SSH– sequence on the C‐termini, the N‐terminal part is the major binding site for the nickel(II) ion, but the formation of dinuclear complexes was also observed. In the [Ni2LH–6]2– complex of hexapeptide, the coordination sphere of the metal ions is saturated with deprotonated Ser‐O–, which does not result in hydrolysis of the peptide. For A4SSH‐NH2, both Ni(II) ions fulfill the conditions for hydrolysis, which was confirmed by HPLC analyses at pH ~ 8.2 and 25 °C. LA - English DB - MTMT ER - TY - JOUR AU - Kastal, Zsuzsa AU - Balabán, Adrienn AU - Vida, Szilvia AU - Kállay, Csilla AU - Nagy, Lajos AU - Várnagy, Katalin AU - Sóvágó, Imre TI - Copper(II), Nickel(II) and Zinc(II) Complexes of Peptide Fragments of Tau Protein JF - MOLECULES J2 - MOLECULES VL - 29 PY - 2024 IS - 10 PG - 18 SN - 1420-3049 DO - 10.3390/molecules29102171 UR - https://m2.mtmt.hu/api/publication/34860740 ID - 34860740 AB - Copper(II), nickel(II) and zinc(II) complexes of various peptide fragments of tau protein were studied by potentiometric and spectroscopic techniques. All peptides contained one histidyl residue and represented the sequences of tau(91–97) (Ac-AQPHTEI-NH2), tau(385–390) (Ac-KTDHGA-NH2) and tau(404–409) (Ac-SPRHLS-NH2). Imidazole-N donors of histidine were the primary metal binding sites for all peptides and all metal ions, but in the case of copper(II) and nickel(II), the deprotonated amide groups were also involved in metal binding by increasing pH. The most stable complexes were formed with copper(II) ions, but the presence of prolyl residues resulted in significant changes in the thermodynamic stability and speciation of the systems. It was also demonstrated that nickel(II) and especially zinc(II) complexes have relatively low thermodynamic stability with these peptides. The copper(II)-catalyzed oxidation of the peptides was also studied. In the presence of H2O2, the fragmentation of peptides was detected in all cases. In the simultaneous presence of H2O2 and ascorbic acid, the fragmentation of the peptide is less preferred, and the formation of 2-oxo-histidine also occurs. LA - English DB - MTMT ER - TY - JOUR AU - Nagy, Lajos AU - Üneri, Haymana Serra AU - Kordován, Marcell Árpád AU - Nagy, Tibor AU - Kuki, Ákos AU - Nyul, Dávid AU - Pál, Petra AU - Erdélyi, Zoltán AU - Zsuga, Miklós AU - Kéki, Sándor TI - Organic Solvent-Based Li–Air Batteries with Cotton and Charcoal Cathode JF - JOURNAL OF THE ELECTROCHEMICAL SOCIETY J2 - J ELECTROCHEM SOC VL - 171 PY - 2024 IS - 4 PG - 12 SN - 0013-4651 DO - 10.1149/1945-7111/ad3857 UR - https://m2.mtmt.hu/api/publication/34802521 ID - 34802521 N1 - Department of Applied Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary Department of Solid State Physics, Faculty of Sciences and Technology, University of Debrecen, PO Box 400, Debrecen, H-4002, Hungary Export Date: 13 June 2024 CODEN: JESOA Funding details: European Commission, EC Funding details: NKFIH K-131989 Funding text 1: Project no. RRF-2.3.1-21-2022-00009, titled National Laboratory for Renewable Energy, was implemented with the support provided by the Recovery and Resilience Facility of the European Union within the framework of Programme Sz\\u00E9chenyi Plan Plus. Furthermore, the work was supported by Hungarian National Scientific Research Fund Grant No. NKFIH K-131989. Special thanks to Victor D. Schepkin for his help in implementing the TQTPPI method and to Gerg\\u0151 R\\u00F3th for the DRT calculations. Funding text 2: Project no. RRF-2.3.1\\u201321\\u20132022\\u201300009, titled National Laboratory for Renewable Energy, was implemented with the support provided by the Recovery and Resilience Facility of the European Union within the framework of Programme Sz\\u00E9chenyi Plan Plus. Furthermore, the work was supported by Hungarian National Scientific Research Fund Grant No. NKFIH K-131989. Special thanks to Victor D. Schepkin for his help in implementing the TQTPPI method and to Gerg\\u0151 R\\u00F3th for the DRT calculations. AB - We report on the construction and investigation of Li–air batteries consisting of a charcoal cathode and cotton texture soaked with different organic solvents containing a lithium triflate (LiOTf) electrolyte. Charcoal was found to be an appropriate cathode for Li–air batteries. Furthermore, cycling tests showed stable operation at over 800 cycles when dimethyl sulfoxide (DMSO) and diethylene glycol dimethyl ether (DEGME) were used as solvents, whereas low electrochemical stability was observed when propylene carbonate was used. The charging, discharging, and long-term discharging steps were mathematically modeled. Electrochemical impedance spectroscopy showed Gerischer impedance, suggesting intensive oxygen transport at the surface of the charcoal cathode. Diffusion, charge transfer, and solid electrolyte interphase processes were identified using distribution of relaxation time analysis. In the polypropylene (PP) membrane soaked with LiOTf in DEGME, three different states of Li ions were identified by 7 Li-triple-quantum time proportional phase increment nuclear magnetic resonance measurements. On the basis of the latter results, a mechanism was suggested for Li-ion transport inside the PP membrane. The activity of the charcoal cathode was confirmed by Raman and cyclic voltammetry measurements. LA - English DB - MTMT ER - TY - JOUR AU - Nagy, Tibor AU - Róth, Gergő AU - Kuki, Ákos AU - Pardi-Tóth, Veronika Csilla AU - Nyul, Dávid AU - Kyzy, Zuura Kaldybek AU - Palacios, Isaac Alexander Iglesias AU - Benedek, Máté AU - Nagy, Lajos AU - Zsuga, Miklós AU - Kéki, Sándor TI - The triumvirate of effective and rapid synthesis, analysis, and artificial intelligence to explore the structure-property relationship of copolymers JF - GIANT J2 - GIANT VL - 17 PY - 2024 PG - 8 SN - 2666-5425 DO - 10.1016/j.giant.2024.100248 UR - https://m2.mtmt.hu/api/publication/34744438 ID - 34744438 AB - Understanding the structure-property relationship is of paramount importance for tailoring copolymers for specific applications. Poly(N-acryloylmorpholine)-block-poly(N-isopropylacrylamide) (PNAM-b-PNIPAM) diblock copolymers were synthesized by reversible addition?fragmentation chain transfer (RAFT) polymerization with varying Mn and composition, providing the basis for deducing structure-property relationships. The chemical structure of the copolymers was analyzed by mass spectrometry (MS). A novel and efficient mass spectrum processing methodology was developed for the detailed analysis of polymers/copolymers that greatly expands the upper mass limit of the time-of-flight (TOF) analyzers in the linear mode up to 20,000 Da. Our method "makes visible" the mass peaks of the individual copolymer species and their isotopologues providing effective and fast automatized analysis. The self-assembly property of the thermoresponsive PNAM-b-PNIPAM diblocks in aqueous solutions was investigated by dynamic light scattering (DLS) experiments, and quantified by determining the incipient temperature of the phase transition. For rapid evaluation, an artificial neural network (ANN) was created to explore the hidden relationships between the structural information obtained by our novel mass analysis method and the properties as well as to predict the self-assembly behavior of the copolymers. LA - English DB - MTMT ER - TY - JOUR AU - Nguyen Huu Huong, Duyen AU - Muthu, Arjun AU - El-Ramady, Hassan AU - Daróczi, Lajos AU - Nagy, Lajos AU - Kéki, Sándor AU - Béni, Áron AU - Csarnovics, István AU - Prokisch, József TI - Optimization of Extraction Conditions to Synthesize Green Carbon Nanodots from Maillard Reaction JF - MATERIALS ADVANCES J2 - MATER ADV VL - 5 PY - 2024 SP - 3499 EP - 3505 PG - 7 SN - 2633-5409 DO - 10.1039/D4MA00037D UR - https://m2.mtmt.hu/api/publication/34720754 ID - 34720754 AB - Carbon nanodots (CNDs) are a class of nanoparticles with unique optical properties with broad applications in various fields. However, synthesizing CNDs with high fluorescence intensity and small size using green... LA - English DB - MTMT ER - TY - PAT AU - BARADÁCS, ESZTER AU - Deák, György AU - Erdélyi, Zoltán AU - Kéki, Sándor AU - Nagy, Lajos AU - Nagy, Tibor AU - Zsuga, Miklós TI - ZN-AIR RECHARGEABLE BATTERY CY - Country:10001(1) PY - 2023 UR - https://m2.mtmt.hu/api/publication/35009826 ID - 35009826 LA - English DB - MTMT ER - TY - PAT AU - Nagy, Tibor AU - Zsuga, Miklós AU - Erdélyi, Zoltán AU - Deák, György AU - Baradács, Eszter AU - Nagy, Lajos AU - Kéki, Sándor TI - Zn-levegő újratölthető elem CY - Country:10001(1) PY - 2023 UR - https://m2.mtmt.hu/api/publication/35009609 ID - 35009609 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Lőrincz, Eszter Boglárka AU - Tóth, Gergely AU - Spolárics, Júlia AU - Herczeg, Mihály AU - Hodek, Jan AU - Zupkó, István AU - Minorics, Renáta AU - Ádám, Dorottya AU - Oláh, Attila AU - Zouboulis, Christos C. AU - Weber, Jan AU - Nagy, Lajos AU - Ostorházi, Eszter AU - Bácskay, Ildikó AU - Borbás, Anikó AU - Herczegh, Pál AU - Bakai-Bereczki, Ilona TI - Mannich-type modifications of (−)-cannabidiol and (−)-cannabigerol leading to new, bioactive derivatives JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 13 PY - 2023 IS - 1 SP - 19618 PG - 20 SN - 2045-2322 DO - 10.1038/s41598-023-45565-7 UR - https://m2.mtmt.hu/api/publication/34316518 ID - 34316518 AB - (−)-Cannabidiol (CBD) and (−)-cannabigerol (CBG) are two major non-psychotropic phytocannabinoids that have many beneficial biological properties. However, due to their low water solubility and prominent first-pass metabolism, their oral bioavailability is moderate, which is unfavorable for medicinal use. Therefore, there is a great need for appropriate chemical modifications to improve their physicochemical and biological properties. In this study, Mannich-type reaction was used for the synthetic modification of CBD and CBG for the first time, and thus fifteen new cannabinoid derivatives containing one or two tertiary amino groups were prepared. Thereafter the antiviral, antiproliferative and antibacterial properties of the derivatives and their effects on certain skin cells were investigated. Some modified CBD derivatives showed remarkable antiviral activity against SARS-CoV-2 without cytotoxic effect, while synthetic modifications on CBG resulted in a significant increase in antiproliferative activity in some cases compared to the parent compound. LA - English DB - MTMT ER - TY - CONF AU - Vadkerti, Bence AU - Lakatos, Csilla AU - Üneri, Haymana Serra AU - Rágyanszki, Anita AU - Farkas, Ödön AU - Juhász, Anett AU - Zsuga, Miklós AU - Kéki, Sándor AU - Nagy, Lajos ED - Majdik, Cornelia TI - Alifás diizocianátok és butan-1-ol reakcióinak kinetikai vizsgálata =$bKinetic study of the reactions between aliphatic diisocyanates and butan-1-ol T2 - XXIX. Nemzetközi Vegyészkonferencia / 29th International Conference on Chemistry PB - Erdélyi Magyar Műszaki Tudományos Társaság (EMT) C1 - Kolozsvár T3 - Nemzetközi Vegyészkonferencia, ISSN 1843-6293 PY - 2023 SP - 61 UR - https://m2.mtmt.hu/api/publication/34274180 ID - 34274180 LA - English DB - MTMT ER - TY - CONF AU - Pardi-Tóth, Veronika Csilla AU - Nagy, Tibor AU - Kordován, Marcell Árpád AU - Róth, Gergő AU - Nagy, Lajos AU - Kuki, Ákos AU - Zsuga, Miklós AU - Kéki, Sándor ED - Majdik, Cornelia TI - Anyagba integrált adatok dekódolása DART-MS ionforrással T2 - XXIX. Nemzetközi Vegyészkonferencia / 29th International Conference on Chemistry PB - Erdélyi Magyar Műszaki Tudományos Társaság (EMT) C1 - Kolozsvár T3 - Nemzetközi Vegyészkonferencia, ISSN 1843-6293 PY - 2023 SP - 58 UR - https://m2.mtmt.hu/api/publication/34272050 ID - 34272050 AB - A molekuláris adattárolás a hagyományos információtároló rendszerekkel azonos szerepet is képes lehet betölteni akár már napjainkban is. A tárolni kívánt információ bináris kódra történő átalakítása által a 0 illetve 1 értékek a kismolekulák hiányát vagy jelenlétét jelezik. Kutatómunkánk során olyan molekulacsoportot szintetizáltunk, amely illékonysága és termikus stabilitása révén alkalmas a kódolást követően DART-MS ionforrással történő visszaolvasásra. Habár a komponensek hasonló szerkezetűek voltak, a tömegcsúcsok intenzitásában mégis jelentős különbségek adódtak az eltérő ionizációs hatásfokok miatt. A tárolt kód hibás visszaolvasásának elkerülése érdekében a koncentrációkat úgy állítottuk be, hogy minden vegyületre hasonló intenzitást kapjunk. Az intenzitásarányok beállítását követően többféle platformon is megvalósítottuk az információ tárolását és hibamentes visszaolvasását. LA - English DB - MTMT ER -