In the present in vitro studies, evidence is provided showing that glutathione (GSH) can undergo spontaneous, nonenzymatic auto-degradation. The initial cleavage of the Glu-Cys bond involves nucleophilic attack of the N-terminal amino group of GSH at the gamma-carbonyl side chain, followed by an unusual cleavage of the Cys-Gly amide bond that is complete within 3-5 weeks in the physiological pH range
Reactive Sulfur Species: Kinetics and Mechanisms of the Reaction of Cysteine Thiosulfinate Ester with Cysteine to Give Cysteine Sulfenic Acid
作者:Péter Nagy、Kelemu Lemma、Michael T. Ashby
DOI:10.1021/jo701813f
日期:2007.11.1
The kinetics and mechanisms of the reaction of cysteine with cysteine thiosulfinate ester in aqueous solution have been studied by stopped-flow spectrophotometry between pH 6 and 14. Two reaction pathways were observed for pH > 12: (1) an essentially pH-independent nucleophilic attack of cysteinate on cysteine thiosulfinate ester, and (2) a pH-dependent fast equilibrium protonation of cysteine sulfenate
Sulfenamides as prodrugs of NH-acidic compounds: A new prodrug option for the amide bond
作者:Victor R. Guarino、Veranja Karunaratne、Valentino J. Stella
DOI:10.1016/j.bmcl.2007.06.037
日期:2007.9
The objective of this report is to introduce the novel concept of utilizing sulfenamides as prodrugs for compounds containing an NH-acidic functionality, particularly weakly acidic amide-type functionalities (amides, ureas, carbarnates, etc.). Included are the syntheses and physicochemical characterizations of some model sulfenamides to illustrate the promise of this new prodrug technology. (C) 2007 Elsevier Ltd. All rights reserved.
Chemical Properties of N-Chlorotaurine Sodium, a Key Compound in the Human Defence System
N-Chlorotaurine (NCT) is known to play an important role in the human defence system. The already proved utility of the sodium salt as a disinfectant in human medicine suggested a thorough investigation of its chemical properties. Chlorine transfer to N-H groups (transhalogenation) and oxidation of thio and aromatic compounds represent its main reactions. Auto-chlorination causes disproportionation forming N,N-dichlorotaurine (NDCT) with K-d = [NDCT][taurine]/f(a)[NCT](2) aH(+) = (4.5 +/- 0.8) x 10(6), while the reaction with ammonium releasing NH2Cl is characterised by K-NHCl2 = [NH2Cl][taurine]/[NCT][NH4+] f(a)(2) = 0.02 +/- 0.004. The verified unique stability and low-level level reactivity of NCT are considered essential for its function in the mammalian defence system and its practical applicability, which manifests itself in an optimal compromise between microbicidal activity and toxicity.
Toennies, Journal of Biological Chemistry, 1937, vol. 122, p. 27 - 46