24645-67-8Relevant academic research and scientific papers
The oxidation of cysteine by electrogenerated octacyanomolybdate (V)
Nekrassova, Olga,Kershaw, Jessica,Wadhawan, Jay D.,Lawrence, Nathan S.,Compton, Richard G.
, p. 1316 - 1320 (2004)
We report on the response of solid carbon electrodes (glassy carbon and boron doped diamond to the one electron oxidation of octacyanomolybdate(IV) in a wide pH range (1-11). Under alkaline conditions the oxidation of octacyanomolybdate(IV) was found to proceed via a EC reaction mechanism, where one electron oxidation to octacyanomolybdate(V) was followed by inner sphere decomposition of the oxidised species. Further, the electrochemical oxidation of octacyanomolybdate(IV) was studied in the presence of thiols (cysteine, homocysteine and glutathione); an electrocatalytic process occurs, where electrochemically generated octacyanomolybdate(V) species is reduced by cysteine back to the parent octacyanomolybdate(IV) species via a E(C)C′ reaction mechanism. DIGISIM modelling was utilised in order to confirm the suggested mechanism and obtain relevant kinetic data.
The mechanism of nitric oxide formation from S-nitrosothiols (thionitrites)
Williams, D. Lyn H.
, p. 1085 - 1091 (1996)
S-Nitrosothiols (RSNO) are easily made by electrophilic nitrosation of thiols and are a convenient source of nitric oxide. Reaction occurs readily (in many cases) in aqueous buffer at pH 7.4 to give in addition the corresponding disulfide RSSR. If oxygen is not rigorously excluded from the solution, then the nitric oxide is converted quantitatively to nitrite ion, whereas in the absence of oxygen nitric oxide can be detected using a commercial NO-probe. Reaction, however, only occurs (apart from the photochemical pathway) if Cu2+ is present. There is often enough Cu2+ in the distilled water-buffer components to bring about reaction, but decomposition is halted if Cu2+ is complexed with EDTA. Experiments with the specific Cu+ chelator neocuproine however show that the true effective reagent is Cu+, formed by reduction of Cu2+ with thiolate ion. Kinetic experiments show that the most reactive nitrosothiols are those which can coordinate bidentately with Cu+, and there is a wide range of reactivity amongst the structures studied. Reactivity is crucially dependent on the concentrations of Cu2+ and RS-. Reaction also occurs, although somewhat more slowly, if the source of copper is the CuII complex with the tripeptide diglycyl-L-histidine (GGH) or as the CuII complex with human serum albumin (HSA). This allows the possibility that nitrosothiols could in principle generate nitric oxide in vivo using the naturally occurring sources of CuII. Rapid exchange of the NO-group in RSNO with thiols occurs, again in aqueous buffer at pH 7.4. This reaction has been established as a nucleophilic substitution reaction by the thiolate ion at the nitroso nitrogen atom. The implications of these results with regard to possible involvement of nitrosothiols in vivo are discussed.
Electropolymerization of cobalt tetraamino-phthalocyanine at reduced graphene oxide for electrochemical determination of cysteine and hydrazine
Mani, Veerappan,Huang, Sheng-Tung,Devasenathipathy, Rajkumar,Yang, Thomas C. K.
, p. 38463 - 38469 (2016)
We describe a simple and elegant electropolymerization method to prepare highly stable tetraamino functionalized cobalt phthalocyanine (pTACoPc) at electrochemically reduced graphene oxide (RGO). The described method efficiently bridges the excellent physicochemical properties of RGO with the rich redox chemistry of TACoPc. Graphene oxide was electrochemically reduced to RGO at the electrode surface along with concominent electropolymerization of TACoPc. The electrochemical studies showed that RGO on pTACoP/GCE increased effective surface area, reduced charge transfer resistance and enhanced electrochemical signal. The RGO-pTACoPc film modified electrode exhibits excellent electrocatalytic ability to oxidize cysteine and hydrazine. To determine cysteine, the RGO-pTACoPc sensor displayed a linear concentration range of 50 nM to 2.0 μM, detection limit of 18.5 nM and sensitivity of 10.19 nA nM-1 cm-2. Besides, the sensor displayed a linear concentration range of 50 nM to 2.6 μM, detection limit of 10 nM and sensitivity of 1.62 nA nM-1 cm-2 to determine hydrazine. The electrocatalytic ability of RGO-pTACoPc shows better performance over other cobalt phthalocyanine derivatives. Furthermore, the described sensor exhibited long-term storage stability, good repeatability and reproducibility. The practical applicability of the sensor has been assessed in biological and water samples.
Complex Formation between Anthraquinone-2,6-disulfonate and a Neutral Zinc Porphyrin. Effects of CTAB Micelles on Complex Stability and Photoinduced Electron Transfer
Degani, Yinon,Willner, Itamar
, p. 5685 - 5689 (1985)
Zinc(II) mexo-tetrakisporphyrin, Zn-TPSPyP0, forms a complex with anthraquinone-2,6-disulfonate, AQS22-.The porphyrin is statically quenched by the quinone acceptor in the complex structure.In the presence of CTAB micelles the complex is separated and AQS22- is bound to micelles.The excited sensitizer decays to a long-lived triplet state (0.5 ms) and induces the reduction of AQS22-.The micelles also function in the charge separation of the electron-transfer products.
The fragmentation of gold nanoparticles induced by small biomolecules
Wang, Tie,Hu, Xiaoge,Dong, Shaojun
, p. 4625 - 4627 (2008)
Spherical gold nanoparticles (3-5 nm) undergo a surprising fragmentation without extra energy imput and are converted into ultrasmall particles (less than 1.5 nm), which is a direct result of electron transfer between gold nanoparticles and cysteine. The Royal Society of Chemistry.
Effect of the structure of the macroheterocyclic ligand on the catalytic properties of tetraarenoporphyrazine metal complexes: II. Oxidation of cysteine, catalyzed by cobalt tetraarenoporphyrazines
Korzhenevskii,Shikova,Koifman,Bykova
, p. 1315 - 1318 (2003)
The catalytic activity of cobalt tetraarenoporphyrazine complexes in heterogeneous oxidation of cysteine is much dependent on the macrocycle structure and is inversely related to the electron-acceptor power of the ligand.
Nitrite reduction mediated by the complex RuIII(EDTA)
Chatterjee, Debabrata,Shome, Sanchari,Jaiswal, Namita,Banerjee, Priyabrata
, p. 13596 - 13600 (2014/11/08)
Reported is the first example of a ruthenium(iii)-complex, Ru III(EDTA) (EDTA4- = ethylenediaminetetraacetate), that mediates O-atom transfer from nitrite to the biological thiols cysteine and glutathione, leading to the formation of [RuIII(EDTA)(NO +)]0. However, at pH below 5.0, the coordinated nitrite ion in the [RuIII(EDTA)(NO2)]2- complex undergoes proton-assisted decomposition, resulting in the formation of a [RuIII(EDTA)(NO+)]0 species. the Partner Organisations 2014.
S-aroylthiooximes: A facile route to hydrogen sulfide releasing compounds with structure-dependent release kinetics
Foster, Jeffrey C.,Powell, Chadwick R.,Radzinski, Scott C.,Matson, John B.
supporting information, p. 1558 - 1561 (2014/04/17)
We report the facile preparation of a family of S-aroylthiooxime (SATO) H2S donors, which are synthesized via a click reaction analogous to oxime formation between S-aroylthiohydroxylamines (SATHAs) and aldehydes or ketones. Analysis of cysteine-triggered H2S release revealed structure-dependent release kinetics with half-lives from 8-82 min by substitution of the SATHA ring. The pseudo-first-order rate constants of substituted SATOs fit standard linear free energy relationships (p = 1.05), demonstrating a significant sensitivity to electronic effects.
Live-cell imaging of cyclopropene tags with fluorogenic tetrazine cycloadditions
Yang, Jun,?e?kute, Jolita,Cole, Christian M.,Devaraj, Neal K.
supporting information; scheme or table, p. 7476 - 7479 (2012/09/08)
Spotlight on lipids: One of the major limitations of tetrazine bioorthogonal cycloadditions is the requirement of bulky dienophile reaction partners. Methylcyclopropene tags were designed capable of reacting rapidly with tetrazines while maintaining stability in aqueous solution. The suitability of these probes for bioconjugation is shown by imaging cyclopropene-modified phospholipids in live human cancer cells (see picture). Copyright
Investigation of reactions postulated to occur during inhibition of ribonucleotide reductases by 2′-azido-2′-deoxynucleotides
Dang, Thao P.,Sobczak, Adam J.,Mebel, Alexander M.,Chatgilialoglu, Chryssostomos,Wnuk, Stanislaw F.
experimental part, p. 5655 - 5667 (2012/09/25)
Model 3′-azido-3′-deoxynucleosides with thiol or vicinal dithiol substituents at C2′ or C5′ were synthesized to study reactions postulated to occur during inhibition of ribonucleotide reductases by 2′-azido-2′-deoxynucleotides. Esterification of 5′-(tert-
