Search results for "Disulfide"

Synthesis of poly(disulfide)s with narrow molecular weight distributions via lactone ring-opening polymerization

2020

We report the first example of controlled polymerization of poly(disulfide)s with narrow molecular weight distributions. 1,4,5-oxadithiepan-2-one (OTP), a disulfide-containing 7-membered ring lactone, was polymerized by using the diphenylphosphate (DPP) catalyzed lactone ring-opening polymerization method. The polymerization proceeded in a living manner, and the resulting polymers displayed very narrow polydispersity index (PDI) values below 1.1 and excellent backbone degradability responding to reducing conditions and UV irradiation.

Degradable cationic nanohydrogel particles for stimuli-responsive release of siRNA.

2014

Well-defined nanogels have become quite attractive as safe and stable carriers for siRNA delivery. However, to avoid nanoparticle accumulation, they need to provide a stimuli-responsive degradation mechanism that can be activated at the payload's site of action. In this work, the synthetic concept for generating well-defined nanohydrogel particles is extended to incorporate disulfide cross-linkers into a cationic nanonetwork for redox-triggered release of oligonucleotide payload as well as nanoparticle degradation under reductive conditions of the cytoplasm. Therefore, a novel disulfide-modified spermine cross-linker is designed that both allows disassembly of the nanogel as well as removal…

Oxidative stress and enzymatic antioxidant mechanisms in essential hypertension

2001

Optical Modification of Monolayer MoS 2 : Deterministic Modification of CVD Grown Monolayer MoS 2 with Optical Pulses (Adv. Mater. Interfaces 10/2021)

2021

[21] Assay of blood glutathione oxidation during physical exercise

1995

Publisher Summary This chapter describes a method to accurately measure glutathione (GSH) and glutathione disulfide (GSSG) in the blood of humans and animals that perform physical exercise. With this method, it is possible to assess the oxidative stress associated with physical exercise by measuring changes in the blood GSH/GSSG ratio. Glutathione measurement is performed by a modification of the glutathione S -transferase method of Brigelius et al. This is based on the conjugation of chlorodinitrobenzene with GSH catalyzed by glutathione S -transferase. The adduct formed, S-(2,4-dinitrophenyl)glutathione, exhibits a maximum of absorbance at 340 nm. The precipitation of proteins is carried …

Role of glutathione in Thiobencarb resistance in the European eel Anguilla anguilla.

2000

Glutathione-dependent defense against xenobiotic toxicity is a multifaceted phenomenon that has been well characterized in mammals. In the present study, eels of species Anguilla anguilla were exposed to 15 ppm of the herbicide thiobencarb (S-4-chlorobenzyl diethylthiocarbamate) for 96 h. Eels exposed to the pesticide were grouped in 24-h intervals according to their time of death, while surviving intoxicated eels constituted another group (live animals). Glutathione content (GSx, GSH, GSSG) was determined in liver and muscle tissues of the dead and live (intoxicated) animals and compared to control values (nonexposed eels). The fish that died before 96 h of exposure were considered suscept…

Plasma selenium levels and oxidative stress biomarkers: a gene-environment interaction population-based study.

2014

The role of selenium exposure in preventing chronic disease is controversial, especially in selenium-repleted populations. At high concentrations, selenium exposure may increase oxidative stress. Studies evaluating the interaction of genetic variation in genes involved in oxidative stress pathways and selenium are scarce. We evaluated the cross-sectional association of plasma selenium concentrations with oxidative stress levels, measured as oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8-oxo-7,8-dihydroguanine (8-oxo-dG) in urine, and the interacting role of genetic variation in oxidative stress candidate genes, in a representative sample of 1445 men and women…

Properties and significance of apoFNR as a second form of air-inactivated [4Fe-4S]·FNR of Escherichia coli

2005

The active form of the oxygen sensor fumarate nitrate reductase regulator (FNR) of Escherichia coli contains a [4Fe-4S] cluster which is converted to a [2Fe-2S] cluster after reaction with air, resulting in inactivation of FNR. Reaction of reconstituted [4Fe-4S].FNR with air resulted within 5 min in conversion to apoFNR. The rate was comparable to the rate known for [4Fe-4S].FNR/[2Fe-2S].FNR cluster conversion, suggesting that apoFNR is a product of [2Fe-2S].FNR decomposition and a final form of air-inactivated FNR in vitro. Formation of apoFNR and the redox state of the cysteinyl residues were determined in vitro by alkylation. FNR contains five cysteinyl residues, four of which (Cys20, Cy…

Thieme Chemistry Journals Awardees – Where Are They Now? Molybdenum(V)-Mediated Synthesis of Nonsymmetric Diaryl and Aryl Alkyl Chalcogenides

2017

Oxidative chalcogenation reaction using molybdenum(V) reagents provides fast access to a wide range of nonsymmetric aryl sulfides and selenides. The established protocol is tolerated by a variety of labile functions, protecting groups, and aromatic heterocycles. In particular, when labile moieties are present, the use of molybdenum(V) reagents provides superior yields compared to other oxidants.

Myocardial Glutathione Alterations in Acute Coronary Occlusion in the Dog

1987

Glutathione (GSH) decreases in dog mycocardium upon acute coronary occlusion when compared with sham-operated dogs. Total glutathione content (GSHeq = GSH + ZGSSG) remains unchanged throughout the experiment (6 h after surgery) in both sham- and acute coronary occlusion-operated dogs. GSSG and GSH/GSSG ratio increases and decreases respectively in all animals but tends to reach the normal value after 6 h in sham-operated dogs. Both parameters (GSSG and GSH/GSSG ratio) remain altered in acute coronary occlusion-operated ones. This alteration of glutathione status in ischemic myocardium is discussed.