- Live-Cell Protein Modification by Boronate-Assisted Hydroxamic Acid Catalysis
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Selective methods for introducing protein post-translational modifications (PTMs) within living cells have proven valuable for interrogating their biological function. In contrast to enzymatic methods, abiotic catalysis should offer access to diverse and new-to-nature PTMs. Herein, we report the boronate-assisted hydroxamic acid (BAHA) catalyst system, which comprises a protein ligand, a hydroxamic acid Lewis base, and a diol moiety. In concert with a boronic acid-bearing acyl donor, our catalyst leverages a local molarity effect to promote acyl transfer to a target lysine residue. Our catalyst system employs micromolar reagent concentrations and affords minimal off-target protein reactivity. Critically, BAHA is resistant to glutathione, a metabolite which has hampered many efforts toward abiotic chemistry within living cells. To showcase this methodology, we installed a variety of acyl groups inE. colidihydrofolate reductase expressed within human cells. Our results further establish the well-known boronic acid-diol complexation as abona fidebio-orthogonal reaction with applications in chemical biology and in-cell catalysis.
- Adamson, Christopher,Kajino, Hidetoshi,Kanai, Motomu,Kawashima, Shigehiro A.,Yamatsugu, Kenzo
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supporting information
p. 14976 - 14980
(2021/09/29)
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- New phthalimide-methionine dyad-based fluorescence probes for reactive oxygen species: Singlet oxygen, hydrogen peroxide, and hypochlorite
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Different reactive oxygen species were detected by the molecular probes 1-3 that were composed of the phthalimide fluorophore as reporter and a methionine-derived thioether side-chain as receptor part. The sulfoxides that were formed as the primary oxidation products show strong fluorescence in the blue-green (430-540?nm) spectral region. Self-sensitized oxidation by singlet oxygen is in general inefficient indicating rapid electron-transfer quenching of the excited probe molecules. With hydrogen peroxide as thermal oxidant conversion to the sulfoxides is slow but can be accelerated by addition of titanium(IV) catalysts, whereas hypochlorite as oxidant behaves much more reactive even under uncatalyzed conditions. Singlet oxygen that is generated by energy transfer from the photosensitizer Rose Bengal was detected by sensor 1a with rate constants of >107M–1?s–1, a typical rate constant for the oxidation of thioethers to sulfoxides.
- Griesbeck, Axel G.,?ngel, Banu,Atar, Murat
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- Synthesis, spectral characterization, electrochemical properties and antimicrobial screening of sulfur containing acylferrocenes
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Several known and eight new sulfur containing acylferrocenes of the general formula FcCO(CH2)nSR (where Fc = ferrocenyl, n = 1 or 2 and R = alkyl, 4-bromobenzyl or 2,6-dichlorobenzyl group) were synthesized in order to test their in vitro antimicrobial activity against 11 bacterial and three fungal/yeast strains. It has been shown that only four of the 14 ketones are completely inactive at the tested dose, while the activities of the other ones were noteworthy. All new compounds were well characterized by IR and NMR spectral data, and their electrochemical properties were investigated by cyclic voltammetry. The X-ray crystal structures of two representative ketones are also presented.
- Ili?, Danijela,Damljanovi?, Ivan,Stevanovi?, Dragana,Vuki?evi?, Mirjana,Radulovi?, Niko,Kahlenberg, Volker,Laus, Gerhard,Vuki?evi?, Rastko D.
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scheme or table
p. 1863 - 1869
(2010/07/04)
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- Extractants for palladium and method of rapidly separating and recovering palladium using the same
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Provided is a novel extractant for palladium capable of improving an extraction rate compared to the conventional extractant, DHS, and also capable of back-extracting palladium using an ammonia solution, and a method of separating and recovering palladium
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Page/Page column 3
(2009/07/25)
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- Studies on umami taste. Synthesis of new guanosine 5′-phosphate derivatives and their synergistic effect with monosodium glutamate
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A number of N2-alkyl and N2-acyl derivatives of guanosine 5′-phosphate (GMP) have been synthesized and tested for their synergistic effect with monosodium L-glutamate (MSG), the prototypical substance imparting umami taste to savory-based foods. Capacities to enhance the taste intensity of MSG (γ values) were estimated through subjective comparisons of MSG/nucleotide mixtures in water with appropriate solutions of MSG alone. Assuming β = γ[nucleotide]/γ[IMP], β values of the N 2-substituted GMPs were found in the range 1.2-5.7. Such values appear to be related to the chain length of the substituent in the 2-position of the purine nucleus and dependent on the replacement of a CH2 group with an S atom and/or with an α-CO group. These findings indicate that the exocyclic NHR group of the guanine moiety is actively implicated in the synergism between GMP derivatives and MSG. Theoretical calculations suggest that an anti conformation is probably assumed by ribonucleotide molecules interacting with umami receptors.
- Cairoli, Paola,Morelli, Carlo F.,Speranza, Giovanna,Manitto, Paolo,Pieraccini, Stefano,Sironi, Maurizio
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supporting information; experimental part
p. 1043 - 1050
(2009/05/08)
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- Process for the production of 1,2-dithiolan-3-pentanoic acid (thioctic acid) and intermediate compounds therefor
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1,2-Dithiolane-3-pentanoic acid (D,L-thioctic acid) of the formula STR1 is prepared by a process comprising (a) reacting a 2-(3-alkylthiopropionyl)-cyclopentanone-1 of the formula STR2 where R is a C1 -C4 alkyl, phenyl or benzyl in aqueous alkaline solution at a temperature of about 20° C. to about 90° C. to form the corresponding carboxylic acid of formula VI STR3 (b) reacting the compound of formula VI with an alkyl mercaptan at a temperature between -20° C. and 0° C. to form the corresponding thioketal of formula VII STR4 (c) reacting the compound of formula VII with sodium in liquid ammonia at a temperature between -60° C. and -10° C. to form the 6,8-dimercaptooctanoic acid of formula VIII STR5 (d) reacting the 6,8-dimercaptooctanoic acid of formula VIII in alkaline solution with an iron (III) salt and oxygen to form the 1,2-dithiolane-3-pentanoic acid of formula IX, or in place of steps (a) through (c) reacting an acid of formula XII STR6 where R1 and R2 are hydrogen, C1 -C4 -alkyl, phenyl or benzyl, with the proviso that both R1 and R2 cannot be benzyl, with sodium in liquid ammonia at a temperature between -60° C. and -10° C. to form the corresponding 6,8-dimercaptooctanoic acid of formula VIII. The compounds of formulae VI, VII, XII are new.
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- [Methionine derivatives with liver protecting activity]
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Some methionine derivatives with the amine group acylated with an aliphatic group bearing a free, esterified or etherified thiol group in the omega position were prepared and tested for protection against CCl4, paracetamol, ethyl alcohol and ethionine int
- Picciola, G.,Zavaglio, G.,Ravenna, F.,Gentili, P.,Tempra-Gabbiati, G.,et al.
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p. 758 - 780
(2007/10/02)
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