Proteins thiol groups

AF Bradbury, DG Smith. The use of 3-bromopropionic acid for the determination of protein thiol groups. J Biochem 131 637-642, 1973. 

Metz JT, Huth JR, Hajduk PJ (2007) Enhancement of chemical rules for predicting compound reactivity towards protein thiol groups. J Comput Aided Mol Des 21(1-3) 139-144... 

Figure 20. Reaction of protein thiol groups as measured by DTNB effects of cystamine intermediary. Penalbumin (O) and BSA (%) were...

Exposure of various cells to ROIs (H2O2, OC1-) in vitro causes a multitude of biochemical alterations including (a) loss of intracellular ATP and NAD+, (b) stimulation of HMP shunt activity, (c) DNA strand breakage, (d) increase in oxidized protein thiol groups, (e) increase in intracellular Ca2+, (f) activation of poly(ADP-ribose) polymerase, (g) alterations in cell morphology, (h) inhibition of many biosynthetic pathways, (i) 51Cr release, (j) intracellular enzyme... 

When analysing the thiol content of membrane proteins, underestimates may arise due to the inaccessibility of some of the SH groups within the hydrophobic portion of the membrane. The following method is used for accurate assessment of membrane protein thiol groups (Deuticke et al 1988)... 

Protein thiol groups also react with water soluble carbodiimides. For example, pa-paine is modified at residue cysteine 25. Tyrosine residues are also modified with carbodiimides. ... 

Figure 9.5 Example substructures with high rates of reactivity against protein thiol groups.The percentage reflects the percentage of cases with experimentally confirmed reactivity as determined in ref. 120.

Blood Cleavage of both organic and inorganic mercury from blood protein thiol groups using hydrochloric acid, extraction of mercury species into toluene as their diethyldithiocarbamate (DDTC) complexes addition of Grignard reagent to toluene phase to form butyl derivatives of the mercury species GC/MPD 0.4 g/L >100% Bulska et al. 1992... 

During the first step, a one-electron oxidation yields a phenoxy radical (Ar-0 ). The presence of the radical was supported by fast flow ESR spectroscopy in the presence of horseradish peroxidase. In the second one-electron oxidation, the phenoxy radical is oxidized to NAPQl. As described in Figure 33.21, the highly electrophilic NAPQl may easily react with glutathione or protein thiol groups according to a Michael-type addition. The attack of liver protein thiol... 

Blood Hg required 200 pL from a whole blood sample drawn into a metal-free tube containing EDTA as an anticoagulant. The sample was mixed with 200 pL of 0.6 M HCl and vortex mixed to free any Hg originally bound to protein thiol groups. Then 1 mL of 0.2 m borate buffer was added. This sample could then be chelated. ... 

As well as the formation of NAPQI there are various other possible metabolic pathways, including deacetylation and radical formation, which may or may not play a role in the hepatotoxicity. The importance of and interrelationships between covalent binding to particular hepatic proteins, cyclical oxidation and reduction of glutathione, oxidation of protein thiol groups and the intracellular calcium level are currently unclear. These events are not mutually exclusive and so it is possible that all are a series of necessary events occurring at particular stages in the development of paracetamol hepatotoxicity. However, covalent binding to protein is still believed to be the important event in the toxicity. 

The ascorbic acid is oxidized by ascorbic acid oxidase in the flour dough to dehydroascorbic acid. In turn, the reduction of dehydroascorbic acid is coupled with the oxidation of protein thiol groups by the enzyme dehydroascorbic acid reductase known to be in wheat (133). 

The first step in determining the sequence of amino acids in a peptide or a protein is to reduce any disulfide bridges in the peptide or protein. A commonly used reducing agent is 2-mercaptoethanol, which is oxidized to a disulfide. Reaction of the protein thiol groups with iodoacetic acid prevents the disulfide bridges from reforming as a result of oxidation by O2. 

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