Equilibrium characterization of the As(III)–cysteine and the As(III)–glutathione systems in aqueous solution

Rey, Nicolás A.; Howarth, Oliver W.; Pereira-Maia, Elene C.

doi:10.1016/j.jinorgbio.2004.03.010

Cited by 131 publications

(100 citation statements)

References 32 publications

(37 reference statements)

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“…It is well-known that thiols reduce arsenic compounds to thiolates such as As(SR) 3 , MeAs(SR) 2 and Me 2 As(SR) [19,20,21,22], which are quantitatively converted by NaBH 4 into the corresponding hydrides [23,24]. Consequently, cold vapor generation by NaBH 4 in the presence of thiols presents an attractive way to estimate the purity of the methylarseno compounds.…”

Section: Resultsmentioning

confidence: 99%

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

et al. 2011

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl-and dimethylarsane by aqueous borohydride and (methyl) arsenates D'Ulivo, Alessandro; Meija, Juris; Mester, Zoltán; Pagliano, Enea; Sturgeon, Ralph E.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21268282&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=21268282&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1007/s00216-011-5503-4Analytical and Bioanalytical Chemistry, 402, 2, pp. 921-933, 2011-10-30 ABSTRACTThe formation of volatile products during the reaction of As(III), As(V), MeAsO(OH) 2 and Me 2 AsO(OH) with aqueous NaBH 4 has been investigated and the formation of arsanes, di-and triarsanes has been detected . The presence of triarsanes is reported here for the first time. Di-and triarsanes are likely formed in condensation cascade reactions, whereas trimethylarsane arises via the transfer of a methyl group. The formation of volatile byproducts is considerably reduced by increasing the acidity of the medium and the concentration of NaBH 4 or by the addition of thiols, such as cysteine. A reaction scheme is proposed which reconciles the evidence reported herein and elsewhere in the literature that is valid for both analytical (trace analysis) and non-analytical reaction conditions.

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Section: Resultsmentioning

confidence: 99%

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

et al. 2011

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“…The interconversion events represent (7.8 AE 1.7) % of all other current steps, that is, 100 (n AB + n BA )/(n PA +n AP +n PB + n BP ; see the Supporting Information), and are over-represented in the selected trace (Figure 1 b). Based on known [16][17][18][19][20][21] and supporting ensemble chemistry, and on the kinetic analysis presented below, we believe that the AsÀS adducts A and B are the diastereomers [22][23][24] formed at the surface of the chiral protein by substitution of one or the other of the enantiotopic hydroxy groups of 4-sulfophenylarsonous acid. Because our measurements were carried out under conditions of dynamic equilibrium, the situation can be represented with a simple kinetic scheme (Figure 1 c).…”

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confidence: 91%

Formation of a Chiral Center and Pyrimidal Inversion at the Single‐Molecule Level

et al. 2007

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The recent development of single-molecule techniques has been largely targeted at solving biological problems; [1][2][3][4][5] for example, protein folding has been examined by means of force spectroscopy, and enzyme kinetics have been investigated by single-molecule fluorescence. These approaches provide insight into individual trajectories that might be obscured in ensemble measurements. In contrast, bondforming and bond-breaking reactions of small molecules in solution have rarely been observed at the single-molecule level. We have developed an approach through which the covalent chemistry of individual molecules can be monitored in an aqueous environment inside a "nanoreactor", that is, the transmembrane protein pore formed by a-hemolysin.[6-9] By monitoring an ionic current driven through the pore by a transmembrane potential, subtle changes in the structures of individual reactants tethered within the lumen can be detected. We now use this approach to follow both the formation of a chiral center at As III (through the making of an As À S bond) and the inversion taking place at that center. The nanoreactor also serves to isolate the relatively short-lived As III adduct and thereby prevent additional reaction steps that would complicate the chemistry. AsÀS bond making and breaking are important reactions in pharmacology, toxicology, [10][11][12][13] and experimental cell biology. [14,15] We earlier reported reversible covalent As À S bond formation between the side chain of a cysteine residue at position 117 in the a-hemolysin pore and 4-sulfophenylarsonous acid (Figure 1 a).[9] Herein, we examine the same reaction at a different position within the nanoreactor (residue 137) and observed two distinct conductance levels, which corresponded to the formation of two As À S adducts at the wall of the protein (see Figure 1 b). Re-examination of the earlier data from the reaction at position 117 also revealed two current levels, but they were very closely spaced. The unitary conductance of P 137-SH -a heteromeric pore with just one of the seven subunits containing a cysteine residue at position 137-in 2 m KCl at À50 mV is (1.71 AE 0.04) nS (this is Figure 1. Two adducts are formed when 4-sulfophenylarsonous acid reacts with the side chain of Cys-137 in the P 137-SH pore. a) Structure of 4-sulfophenylarsonous acid and schematic of the P 137-SH pore. In aqueous solution, the dehydrated form, that is, 4-sulfophenylarsane oxide, may exist in equilibrium with 4-sulfophenylarsonous acid. The P 137-SH pore consists of six cysteine-free wild-type subunits (green) and one mutated subunit (blue) in which Gly 137 is substituted by Cys. The sulfur atom of the Cys residue is shown in yellow, the carboxy oxygen of residue 137 in red. b) Single-channel recording at À50 mV and 23 8C with a buffer containing 2 m KCl, 80 mm 3-(4-morpholinyl)-1-propanesulfonic acid (MOPS), 100 mm ethylenediaminetetraacetate (EDTA) (pH 8.4) in both chambers. 4-Sulfophenylarsonous acid (100 mm) was in the trans chamber. The current levels corresponding ...

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“…Above pH ~ 8 the A 235nm vs. pH curve seems to follow the formation of biscomplexes. It has to be noted, however, that deprotonated thiol groups also possess a relatively intense absorption around  = 236 nm assigned to an n  * transition [52]. Since the suggested bis-complex formation and deprotonation of the Cys residues of free PS take 12 place in a similar pH-range, the observed increase of absorbance above pH ~ 8 is very likely the result of parallel processes.…”

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confidence: 95%

Competition of zinc(II) with cadmium(II) or mercury(II) in binding to a 12-mer peptide

Jancsó

Gyurcsik

Mesterházy

et al. 2013

Journal of Inorganic Biochemistry

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Equilibrium characterization of the As(III)–cysteine and the As(III)–glutathione systems in aqueous solution

Cited by 131 publications

References 32 publications

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

Condensation cascades and methylgroup transfer reactions during the formation of arsane, methyl- and dimethylarsane by aqueous borohydride and (methyl) arsenates

Formation of a Chiral Center and Pyrimidal Inversion at the Single‐Molecule Level

Competition of zinc(II) with cadmium(II) or mercury(II) in binding to a 12-mer peptide

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