78348-28-4Relevant articles and documents
Enhancement of amino acid detection and quantification by electrospray ionization mass spectrometry
Yang, Wen-Chu,Mirzaei, Hamid,Liu, Xiuping,Regnier, Fred E.
, p. 4702 - 4708 (2006)
A new strategy for amino acid analysis is reported involving derivatization with an N-hydroxysuccinimide ester of N-alkylnicotinic acid (C n-NA-NHS) followed by reversed-phase chromatography and electrospray ionization mass spectrometry (RPC-MS). Detection sensitivity increased as the N-alkyl chain length of the nicotinic acid derivatizing agent was increased from 1 to 4. N-Acylation of amino acids with the Cn-NA-NHS reagents in water produced a stable product in roughly 1 min using a 4-fold molar excess of derivatizing agent in 0.1 M sodium borate buffer at pH values ranging from 8.5 to 10. Some O-acylation of tyrosine was also observed, but the product hydrolyzed within a few minutes at pH 10. The cystine product also degraded slowly over the course of a few days from reduction of the disulfide bond to form cysteine. The retention time of Cn-NA derivatized amino acids was lengthened in reversed-phase chromatography to the extent that polar amino acids were retained beyond the solvent peak, particularly in the cases of the C3-NA and C4-NA derivatives. Complete resolution of 18 amino acids was achieved in 28 min using the C4-NA-NHS reagent. Compared to N-acylation with benzoic acid, derivatization with C 4-NA-NHS increased MS detection sensitivity 6-80-fold. This was attributed to the surfactant properties of the Cn-NA-NHS reagents. The quaternary amine increased the charge on amino acid conjugates while the presence of an adjacent alkyl chain further increased ionization efficiency by apparently enhancing amino acid migration to the surface of electrospray droplets. Further modification of the Cn-NA-NHS reagents with deuterium was used to prepare coded sets of derivatizing agents. These coding agents were used to differentially code samples and after mixing carry out comparative concentration measurements between samples using extracted ion chromatograms to estimate relative peak areas of derivatized amino acids.
Highly sensitive quantitative analysis of nicotianamine using LC/ESI-TOF-MS with an internal standard
Wada, Yasuaki,Yamaguchi, Isomaro,Takahashi, Michiko,Nakanishi, Hiromi,Mori, Satoshi,Nishizawa, Naoko K.
, p. 435 - 441 (2007)
A highly sensitive quantitative method for analyzing nicotianamine (NA) by liquid chromatography/electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOF-MS) is reported. Fluorenylmethoxycarbonylation of nicotianamine reduced its polarity and enabled its retention in a reversed-phase column. The adoption of Nε-nicotyllysine (NL) as an internal standard ensured reliable quantification by giving a linear calibration curve drawn between the NA/NL molar ratios of standard solutions injected and the NA/NL area ratios in mass chromatograms. The high sensitivity of this analytical method allowed us to measure the amount of NA. This analytical method has applications to all research concerning NA.
Structure-activity relationships of N-terminal variants of peptidomimetic tissue transglutaminase inhibitors
Adhikary, Gautam,Cundy, Nicholas J.,Eckert, Richard L.,Eisinga, Sarah,Firoozi, Neda,Gates, Eric W. J.,Keillor, Jeffrey W.,Leccese, Jessica,McNeil, Nicole M. R.,Tyndall, Joel D. A.
, (2022/02/16)
Tissue transglutaminase (TG2) is a multifunctional protein that catalyses protein crosslinking in the extracellular matrix, and functions as an intracellular G-protein. While both activities have been associated with human diseases, its role as a G-protein has been linked to cancer stem cell survival and maintenance of a metastatic phenotype. Recently we have shown that targeted covalent inhibitors (TCIs) can react selectively with the enzyme active site of TG2, to allosterically abolish its ability to bind GTP. In the present work, we focused on the variation of the N-terminal group of these peptidomimetic inhibitors, in order to enhance efficiency, while reducing log P and the number of rotatable bonds. This approach led to the synthesis and evaluation of 41 novel inhibitors, some of which had greatly improved efficiency and affinity for TG2 (e.g. TCI 72: KI = 1.0 μM, kinact/KI = 4.4 × 105 M?1 min?1). Molecular modelling provided a hypothetical binding mode for these TCIs. The most efficient inhibitors were evaluated further and shown to have excellent isozyme selectivity, to block GTP binding, and to have improved pharmacokinetic properties, as expected. Their biological activity was also confirmed, in a cellular invasion assay, although with less potency than expected.
Halide-Accelerated Acyl Fluoride Formation Using Sulfuryl Fluoride
Foth, Paul J.,Malig, Thomas C.,Yu, Hao,Bolduc, Trevor G.,Hein, Jason E.,Sammis, Glenn M.
, p. 6682 - 6686 (2020/09/02)
Herein, we report a new one-pot sequential method for SO2F2-mediated nucleophilic acyl substitution reactions starting from carboxylic acids. A mechanistic study revealed that SO2F2-mediated acid activation proceeds via the anhydride, which is then converted to the corresponding acyl fluoride. Tetrabutylammonium chloride or bromide accelerate the formation of acyl fluoride. Optimized halide-accelerated conditions were used to synthesize acyl fluorides in 30-80percent yields, and esters, amides, and thioesters in 72-96percent yields without reoptimization for each nucleophile.
SIRT1 ACTIVATING COMPOUNDS
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Page/Page column 63; 65-66, (2020/05/21)
Provided herein are methods and compositions for preventing or treating aging, or an aging-related disorder, a disorder associated with inflammation, or for modulating an immune response in a subject in need thereof. In some embodiments, the methods comprise administering to the subject an effective amount of a compound of Formulas I-XIII.
Synthesis and Biochemical Evaluation of Nicotinamide Derivatives as NADH Analogue Coenzymes in Ene Reductase
Falcone, Natashya,She, Zhe,Syed, Jebreil,Lough, Alan,Kraatz, Heinz-Bernhard
, p. 838 - 845 (2019/02/07)
Nicotinamide and pyridine-containing conjugates have attracted a lot of attention in research as they have found use in a wide range of applications including as redox flow batteries and calcium channel blockers, in biocatalysis, and in metabolism. The interesting redox character of the compounds’ pyridine/dihydropyridine system allows them to possess very similar characteristics to the natural chiral redox agents NAD+/NADH, even mimicking their functions. There has been considerable interest in designing and synthesizing NAD+/NADH mimetics with similar redox properties. In this research, three nicotinamide conjugates were designed, synthesized, and characterized. Molecular structures obtained through X-ray crystallography were obtained for two of the conjugates, thereby providing more detail on the bonding and structure of the compounds. The compounds were then further evaluated for biochemical properties, and it was found that one of the conjugates possessed similar functions and characteristics to the natural NADH. This compound was evaluated in the active enzyme, enoate reductase; like NADH, it was shown to help reduce the C=C double bond of three substrates and even outperformed the natural coenzyme. Kinetic data are reported.
Structure-Activity Relationships of Potent, Targeted Covalent Inhibitors That Abolish Both the Transamidation and GTP Binding Activities of Human Tissue Transglutaminase
Akbar, Abdullah,McNeil, Nicole M. R.,Albert, Marie R.,Ta, Viviane,Adhikary, Gautam,Bourgeois, Karine,Eckert, Richard L.,Keillor, Jeffrey W.
, p. 7910 - 7927 (2017/10/06)
Human tissue transglutaminase (hTG2) is a multifunctional enzyme. It is primarily known for its calcium-dependent transamidation activity that leads to formation of an isopeptide bond between glutamine and lysine residues found on the surface of proteins, but it is also a GTP binding protein. Overexpression and unregulated hTG2 activity have been associated with numerous human diseases, including cancer stem cell survival and metastatic phenotype. Herein, we present a series of targeted covalent inhibitors (TCIs) based on our previously reported Cbz-Lys scaffold. From this structure-activity relationship (SAR) study, novel irreversible inhibitors were identified that block the transamidation activity of hTG2 and allosterically abolish its GTP binding ability with a high degree of selectivity and efficiency (kinact/KI > 105 M-1 min-1). One optimized inhibitor (VA4) was also shown to inhibit epidermal cancer stem cell invasion with an EC50 of 3.9 μM, representing a significant improvement over our previously reported "hit" NC9.
Palladium-Catalyzed Carbonylation of (Hetero)Aryl, Alkenyl and Allyl Halides by Means of N-Hydroxysuccinimidyl Formate as CO Surrogate
Barré, Ana?s,T?nta?, Mihaela-Liliana,Alix, Florent,Gembus, Vincent,Papamica?l, Cyril,Levacher, Vincent
, p. 6537 - 6544 (2015/10/05)
An efficient Pd-catalyzed carbonylation protocol is described for the coupling of a large panel of aryl, heteroaryl, benzyl, vinyl and allyl halides 2 with the unusual N-hydroxysuccinimidyl (NHS) formate 1 as a CO surrogate to afford the corresponding valuable NHS esters 3. High conversion to the coupling products was achieved with up to 98% yield by means of Pd(OAc)2/Xantphos catalyst system.
General method for the preparation of active esters by palladium-catalyzed alkoxycarbonylation of aryl bromides
De Almeida, Angelina M.,Andersen, Thomas L.,Lindhardt, Anders T.,De Almeida, Mauro V.,Skrydstrup, Troels
supporting information, p. 1920 - 1928 (2015/02/19)
A useful method was developed for the synthesis of active esters by palladium-catalyzed alkoxycarbonylation of (hetero)aromatic bromides. The protocol was general for a range of oxygen nucleophiles including N-hydroxysuccinimide (NHS), pentafluorophenol (PFP), hexafluoroisopropyl alcohol (HFP), 4-nitrophenol, and N-hydroxyphthalimide. A high functional group tolerance was displayed, and several active esters were prepared with good to excellent isolated yields. The protocol was extended to access an important synthetic precursor to the HIV-protease inhibitor, saquinavir, by formation of an NHS ester followed by acyl substitution.
Pyridylthiourea-grafted polyethylenimine offers an effective assistance to siRNA-mediated gene silencing in vitro and in vivo
Creusat, Gaelle,Thomann, Jean-Sébastien,Maglott, Anne,Pons, Bénédicte,Dontenwill, Monique,Guérin, Eric,Frisch, Benoit,Zuber, Guy
experimental part, p. 418 - 426 (2012/06/17)
Success of synthetic interfering nucleic acids (siRNAs)-based therapy relies almost exclusively on effective, safe and preferably nanometric delivery systems which can be easily prepared, even at high concentrations. We prepared by chemical synthesis vari
