What is the reaction that creates disulfide bridges?

What is the function of disulfide bridges? Different biologics have different numbers and formations of disulfide bridges that should be fully assessed during protein characterization studies (providing that the expected primary amino acid sequence of the product contains the amino acid cysteine). This is also a requirement of the regulatory document ICH Topic Q6B: If, based on the gene sequence for the desired product, cysteine residues are expected, the number and positions of any free sulfhydryl groups and/or disulfide bridges should be determined, to the extent possible. Peptide mapping (under reducing and non-reducing conditions), mass-spectrometry, or other appropriate techniques may be useful for this evaluation. Disulfide Bridge Analysis: Methodology BioPharmaSpec scientists are skilled in the analysis and interpretation of free sulfhydryl groups and disulfide bridges. Peptide mapping post-digestion with a specific protease, followed by analysis using on-line LC/ES-MS and/or LC/ES-MS/MS prior to and following reduction, provides the data necessary for a full assessment of disulfide bridges and free thiols. During this experiment, a proteolytic agent (enzyme, chemical digest or combination of the two) is designed to digest between the Cysteine residues in the primary amino acid sequence. The resulting peptide mixture, potentially containing disulfide bridged peptides and free thiol containing peptides, is analyzed by mass spectrometry prior to and following reduction. Keywords: What is the reaction that forms a disulphide bridge? A) Reduction B) Oxidation C) Hydrolysis D) Phosphorylation E) Condensation #disulfideBridge #aminoAcids #polypeptide #proteins #polypeptideChain