China 
Africa 
Explore chapters and articles related to this topic
Biophysical and Biochemical Characterization of Peptide, Protein, and Bioconjugate Products
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Tapan K. Das, James A. Carroll
The presence of thiols may indicate incompletely formed disulfides in a biotherapeutic protein in which all cysteines are expected to form disulfide bonds. Thiols may be detected using Ellman’s reagent followed by colorimetric detection. Alternatively, thiol-specific chemistry may be used to label free cysteine residues with a chromophore or fluorophore, followed by quantitative detection [59].
Alteration of thiol-disulfide homeostasis in workers occupationally exposed to arsenic
Published in Archives of Environmental & Occupational Health, 2018
Murat Büyükşekerci, Ceylan Bal, Utku Serkant, Meşide Gündüzöz, Murat Alışık, Engin Tutkun, Ömer Hınç Yılmaz
Thiol-disulfide homeostasis parameters were determined as described previously by Erel and Neşelioğlu.16 Briefly, venous blood samples of study participants were collected in EDTA-containing trace-element tubes (BD Vacutainer), and serum was separated by centrifugation at 1,500 × g for 10 minutes. The samples were processed instantly or kept at −80°C. A Cobes c50 automated analyzer (Roche) and a Shimadzu UV-1800 spectrophotometer, having a temperature-controlled cuvette holder, were used. Native and total thiol concentrations were determined at the same time in two separate vessels as a paired test. In the first vessel, native thiol concentration was determined by a modified Ellman reagent, 5,5′-dithiobis-(2-nitrobenzoic) acid (DTNB). In the parallel vessel, sodiumborohydrate (NaBH4) was used to reduce dynamic disulfide bonds to free thiol groups. NaBH4 remnants were eliminated by formaldehyde, which prevents extra reduction of DTNB. Formaldehyde also prevents the reduction of the disulfide bond that is formed after the DTNB reaction. The total thiol concentration of the sample was also determined using modified Ellman reagent. Disulfide concentration was calculated by subtracting native thiol from total thiol and dividing the result by 2. The unit is expressed as μmol/L. Other parameters (disulfide/native thiol, disulfide/total thiol, and native /total thiol ratios) were obtained by calculations.