Chemistry
Thiol Reactions
Thiol reactions involve the chemical reactions of compounds containing a sulfhydryl group (–SH). Thiol groups are highly reactive and can undergo various types of reactions, including oxidation, reduction, and formation of disulfide bonds. These reactions are important in organic synthesis, biochemistry, and industrial processes due to the unique properties and reactivity of thiol compounds.
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3 Key excerpts on "Thiol Reactions"
eBook - PDF- Hans Neurath(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
Some degree of specificity was observed in the formation of a disulfide bond or a sulfonic acid (Sokolovsky et al., 1969), but in most cases the lack of specificity and the possibility of overoxidation in reactions mediated by these reagents detract from their usefulness for the modification of protein sulfhydryl groups. The reactions of tetrathionate, cystamine monosulfoxide, alkyl al-kanethiolsulfonate, or alkylcarbonylalkyl disulfide with sulfhydryl groups are similar to those of disulfides. The sulfhydryl groups can be regenerated with excess thiols (Pihl and Lange, 1962). These reagents 3. The Role of Sulfur in Proteins 263 have been found useful in the reversible protection of sensitive SH groups in some sulfhydryl enzymes during the modification of other functional groups (Liu, 1967; Kassab et al., 1968; Smith et al., 1975): Protein—SH + S 4 0 6 2 τ± protein—S—S—S0 3 + S 2 O s 2 - + H + (30) For example, after conversion of the sulfhydryl group to the sulfenyl thiosulfate at the active site of streptococcal proteinase, the histidine residue at the active site would be readily alkylated by the reactive substrate analogue, α-N-bromoacetylarginine methyl ester (Liu, 1967). The reversible inactivation of pig muscle glyceraldehyde-3-phosphate dehydrogenase by tetrathionate involves the binding of one equivalent of thiosulfate and the disappearance of one SH group per enzyme subunit (Parker and Allison, 1969). By treatment with thiols, the thiosulfate group can be displaced and the enzyme reacti-vated. If, however, the sulfenyl thiosulfate derivative is warmed for a short period or is subjected to mildly denaturing conditions, thiosul-fate ion is expelled and the enzyme becomes irreversibly inactivated.
- Andrew Lowe, Christopher Bowman(Authors)
- 2013(Publication Date)
- Royal Society of Chemistry(Publisher)
are used intensively in the conjugation of polymers with proteins/ polypeptides. 1–5 These chemical concepts have also found application in polymer chemistry 6–23 and as such, the book at hand on ‘‘Thiol-X Chemistries in Polymer and Materials Science’’ represents a comprehensive compilation of the various aspects of thiol chemistries employed in the preparation and functionalization of polymers. The present chapter covers the particularly useful reaction of thiols with thiosulfonates, yielding asymmetric disulfides. Because of the ease of cleaving disulfides on demand by mild reduction, these reactions offer the possibility of reversible functionalisation. 21,24,25 Methanethiosulfonates (MTS) have found broad utilization in biochemistry. Due to their highly selective reactivity toward thiols in water and fast reaction rates, functional MTS reagents have particularly been exploited for the site-specific modification of cysteine residues of proteins, 26–28 including fluorescent labeling, 29 glycosylation, 30–32 and biotinylation. 33 In particular, ion channel proteins have been targeted with charged MTS reagents, giving insights into their structure and function by way of the substituted cysteine accessibility method (SCAM). 29,34–42 Site directed spin labeling with a radical modified MTS reagent and measurement of the electron paramagnetic resonance spectrum has been used to map the topography of membrane proteins and to determine secondary structures. 43–45 The versatility of MTS reactions has recently been adapted to polymer chemistry and represents a sub-class of the manifold thiol-X reactions employed in the functionalization of polymers. When functional thiosulfonates are used, the respective functional groups can be installed in polymers. In the following sections, first, the reactivity and synthesis of functional thiosulfonates and their utilization will be described, followed by a section on polymeric thiosulfonates.
eBook - PDFHydrogen Sulfide
Chemical Biology Basics, Detection Methods, Therapeutic Applications, and Case Studies
- Michael D. Pluth, Binghe Wang(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
Redox Biol. 26: 101281. https://doi.org/10.1016/j.redox.2019.101281. 103 Szajewski, R.P. and Whitesides, G.M. (1980). Rate constants and equilib- rium constants for thiol-disulfide interchange reactions involving oxidized glutathione. J. Am. Chem. Soc. 102: 2011–2026. https://doi.org/10.1021/ ja00526a042. 104 Bogdándi, V., Ida, T., Sutton, T.R. et al. (2019). Speciation of reactive sulfur species and their reactions with alkylating agents: do we have any clue about what is present inside the cell? Br. J. Pharmacol. 176: 646–670. https://doi .org/10.1111/bph.14394. 105 Kabil, O., Motl, N., Strack, M. et al. (2018). Mechanism-based inhibition of human persulfide dioxygenase by γ-glutamyl-homocysteinyl-glycine. J. Biol. Chem. 293: 12429–12439. https://doi.org/10.1074/jbc.RA118.004096. 106 Jencks, W.P. and Carriuolo, J. (1960). Reactivity of nucleophilic reagents toward esters. J. Am. Chem. Soc. 82: 1778–1786. https://doi.org/10.1021/ ja01492a058. 107 Edwards, J.O. and Pearson, R.G. (1962). The factors determining nucleophilic reactivities. J. Am. Chem. Soc. 84: 16–24. https://doi.org/10.1021/ja00860a005. 108 Um, I.-H., Im, L.-R., and Buncel, E. (2010). Pitfalls in assessing the α-effect: reactions of substituted phenyl methanesulfonates with HOO(-), OH(-), and substituted phenoxides in H(2)O. J. Org. Chem. 75: 8571–8577. https://doi.org/ 10.1021/jo101978x. 109 Hoz, S. (1982). The α effect: on the origin of transition-state stabilization. J. Org. Chem. 47: 3545–3547. https://doi.org/10.1021/jo00139a033. 110 Garver, J.M., Gronert, S., and Bierbaum, V.M. (2011). Experimental validation of the α-effect in the gas phase. J. Am. Chem. Soc. 133: 13894–13897. https:// doi.org/10.1021/ja205741m. 111 Benaïchouche, M., Bosser, G., Paris, J., and Plichon, V. (1990). Relative nucleophilicities of aryldisulphide and thiolate ions in dimethylacetamide estimated from their reaction rates with alkyl halides. J. Chem. Soc. Perkin Trans. 2 (8): 1421–1424. https://doi.org/1421-1424.
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