scholarly journals The use of 3-bromopropionic acid for the determination of protein thiol groups

1973 ◽  
Vol 131 (4) ◽  
pp. 637-642 ◽  
Author(s):  
A. F. Bradbury ◽  
D. G. Smyth
Keyword(s):  
Carboxylic Acid ◽  
Intramolecular Cyclization ◽  
Iodoacetic Acid ◽  
Cyclization Reaction ◽  
Thiol Groups ◽  
Protein Thiol

S-Carboxymethylcysteine, formed by the reaction of iodoacetic acid with cysteine, was found to undergo intramolecular cyclization to yield 3-oxo-(2H,3H,5H,6H-1,4-thiazine)-5-carboxylic acid. The cyclization was studied under various conditions and the product was isolated and characterized. S-Carboxyethylcysteine, formed by the reaction of 3-bromopropionic acid with cysteine, did not undergo the cyclization reaction. The use of 3-bromopropionic acid was examined as an alternative to iodoacetic acid for the protection and determination of protein thiol groups.

scholarly journals Thiol and disulphide contents of hen ovalbumin. C-Terminal sequence and location of disulphide bond

1970 ◽  
Vol 116 (4) ◽  
pp. 555-561 ◽  
Author(s):  
L. A. Fothergill ◽  
J. E. Fothergill
Keyword(s):  
Acetic Acid ◽  
Iodoacetic Acid ◽  
Disulphide Bond ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Acid Oxidation ◽  
Double Labelling ◽  
Thiol Groups ◽  
Terminal Sequence

1. The thiol and disulphide contents of hen ovalbumin were investigated by p-chloromercuribenzoate titration, by determination of cysteic acid content after performic acid oxidation, by measurement of uptake of radioactive iodoacetic acid, and by assay of S-aminoethylcysteine after reaction with ethyleneimine. All results showed that ovalbumin had 6 half-cystine residues. Experiments with and without reducing agents demonstrated that there were 4 thiol groups and 1 disulphide bond. 2. A peptide containing equimolar amounts of S-carboxymethyl-cysteine, serine, valine and proline, but no lysine or arginine, was obtained by radioactive labelling of the cysteine residues with iodo[14C]acetic acid followed by electrophoretic and chromatographic separation of tryptic digests. It was concluded that the C-terminal sequence of ovalbumin is -Cys-Val-Ser-Pro. 3. The location of the disulphide bond was studied by using a double-labelling technique. It was shown that one end of the disulphide was located in this C-terminal peptide.

Effect of Vernonia cognata on oxidative damage induced by ethanol in rats

2010 ◽  
Vol 30 (7) ◽  
pp. 675-684 ◽  
Author(s):  
CS Mota ◽  
RB Freitas ◽  
ML Athayde ◽  
AA Boligon ◽  
PR Augusti ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
High Performance ◽  
Tissue Injury ◽  
Antioxidant Effect ◽  
Gastric Tissue ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Stress Markers ◽  
Hydroethanolic Extract ◽  
And Oxidative Stress

Free radicals production and oxidative stress play a central role in injuries caused by ethanol (EtOH) on gastric mucosal. Thus, strategies to counteract EtOH toxicity are highly desirable. This study was aimed at evaluating whether Vernonia cognata extract would reduce EtOH effects in rats. Rats received Vernonia cognata extract (0, 1 and 2 g/kg bw, by gavage) 1 hour after EtOH had been administered (0 or 70%, 0.5 mL/100 g bw, by gavage) and were killed 1 hour after Vernonia cognata extract administration. The stomach was removed for macroscopic and histopathological evaluation, as well as, oxidative stress markers such as lipoperoxidation (LPO) and non-protein thiol groups (NPSH) levels and catalase (CAT) activity. EtOH acute exposure increased LPO and decreased NPSH levels and CAT activity along with macroscopic and microscopic lesions in gastric tissue, confirming the involvement of oxidative stress in EtOH toxicity. Vernonia cognata extract attenuated oxidative and histopathological features induced by EtOH at all evaluated doses. Moreover, both studied doses of Vernonia cognata extract caused an increase in NPSH levels per se. However, only the dose of 2 g/kg reverted all macroscopic changes caused by EtOH toxicity. The protective effect of the extract could be attributed to antioxidant molecules present in the extract, such as flavonoids and phenolic acids, which were quantified by high performance liquid chromatography (HPLC). Thus, an antioxidant effect of the extract leads to a protection on gastric tissue. Our results indicate that Vernonia cognata hydroethanolic extract could have a beneficial role against EtOH toxicity by preventing oxidative stress and gastric tissue injury.

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