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The Modification of Cystine — Cleavage of Disulfide Bonds
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
This reaction has been adapted to the controlled reduction of disulfide bonds in proteins in the absence of denaturing agents.21 In the example presented, the disulfide bonds of bovine serum albumin were cleaved at pH 7.0 (0.1 M phosphate) at 40°C in the presence of 0.1 M sodium sulfite and simultaneously converted to the S-sulfo derivatives with oxygen and 0.4 mM cupric sulfate. The rate of reaction decreased markedly above pH 7.0.
Soluble Mediators of Cellular Cooperation: The Cytokines
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Genetics and structure. The IL-4 gene is located in the cytokine gene complex of chromosome 5 (Figure 7–2). The promoter region contains a xB-like sequence element. IL-4 is a heavily glycosylated protein of Mr 18–19 kDa; carbohydrate is not required for biological activity. The molecule contains three disulfide bonds.
Excitotoxicity and Nitric Oxide
Published in Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin, Brain Injury and Pediatric Cardiac Surgery, 2019
Sodium nitroprusside has a pentocyanoferrate moiety and an NO+ moiety. The NO+ can be transferred to a redox site on the NMDA receptor by a complicated chemical reaction with an intermediate.5 That reaction can facilitate disulfide bond formation.
Molecular effects of ozone on amino acids and proteins, especially human hemoglobin and albumin, and the need to personalize ozone concentration in major ozone autohemotherapy
Published in Critical Reviews in Clinical Laboratory Sciences, 2023
Fouad Mehraban, Arefeh Seyedarabi
During oxidation with different oxidants such as H2O2, the free thiol group of Cys in HSA can form sulfenic acid as a key intermediate in thiol oxidation processes, which can play a role in the formation of mixed disulfides, for example, the reaction of a protein sulfenic acid (HSA-SOH) with GSH and the formation of glutathionylated proteins (HSA-SSG) [118,127]. The formation of disulfide bonds can also occur in other molecules in the blood that contain the sulfhydryl group. Disulfides are generally formed as a result of the oxidation of thiol groups of Cys and also through thiol-disulfide reactions caused by oxidants, which lead to the generation of intermolecular protein-protein crosslinks such as the crosslink formed between Cys36 from the Cys36-Cys97 disulfide of C-reactive protein with the thiol of Cys34 from HSA [128].
Thiol–Disulfide Homeostasis and Serum Ischemia Modified Albumin Levels in Patients with Primary Open–Angle Glaucoma
Published in Current Eye Research, 2019
Yucel Karakurt, Cuma Mertoglu, Gamze Gok, Turgay Ucak, Nurdan Tasli, Erel Icel, Ozcan Erel
In this study we investigated the alterations in thiol/disulfide homeostasis in POAG and determined that, plasma disulfide levels were elevated in patients with glaucoma. Due to the enhanced thiol–disulfide homeostasis, plasma thiol levels were decreased defining an augmented oxidative stress status. The increase in the Disulfide/Total thiol and Disulfide/Native thiol ratios and the decrease in the Native thiol/Total thiol ratio also show that the thiol/disulfide redox balance system shifted to the side of disulfide bond formation. Disulfide levels were significantly correlated with the stage and the duration of the disease while there was a negative correlation between thiols and the stage and the duration of the disease. On the other hand, IMA and adjusted IMA levels were both significantly decreased in POAG patients but they did not show any correlation with the disease severity.
Thiol/disulfide homeostasis as a marker of oxidative stress in rosacea: a controlled spectrophotometric study
Published in Cutaneous and Ocular Toxicology, 2019
Sertac Sener, Ayse Akbas, Fadime Kilinc, Pervin Baran, Ozcan Erel, Akin Aktas
In the present study, the findings related to ratios (ratios 1, 2, and 3) indicated that the thiol/disulfide balance was shifted towards disulfides in the patient group (p < 0.05 for all). Moreover, the levels of native thiol and total thiol were observed to be decreased in the rosacea patients than in the controls; however, the difference did not achieve statistical significance. In conclusion, based on the results of the present study, it was thought that ROS which were generated by the factors triggering rosacea led to the formation of disulfide bonds and to a decrease in thiol levels by oxidizing thiol groups in the organism. It is possible to consider thiol/disulfide homeostasis as a biomarker indicating the oxidative stress in rosacea. Moreover, based on our results, it could be predicted that antioxidant treatments including thiols might be effective in the course of rosacea.