Disulphide bonds exchange reactions

Insulin contains three disulphide bonds, namely two interchain disulphide bonds and one intrachain structure in the A chain. These disulphide bonds tend to undergo slow exchange reactions when exposed to acid ... 

Other chemical degradation pathways include -elimination, which can lead to racemization and disulphide exchange reactions. The amino acids that may undergo P-elimination include Cys, Ser, Thr, Phe, and Lys (40) and occur especially at alkaline pH (64). The reduction and oxidation of the disulphide bonds are often accompanied by a considerable change in the protein conformation (23,33). An example is the secondary structure of insulin that is disrupted or completely lost when the disulphide bonds are broken (23). The disulphide bond disruption or interchange can also result in an altered three-dimensional structure and therefore a possible loss of activity (40) or aggregation (29). For further details, the reader is directed to the following reviews and book chapters (30,40,62,65). 

Reviews cover the topics alkynethiolates in synthesis " oxygen-exchange reactions of sulphoxides sulphonyldiazomethanes C—S bond cleavage acyl isothiocyanates radical reactions of sulphur compounds addition of sulphenyl halides to olefins " sulphenamidcs mercaptoethylation of amines sulphur as a chiral centre " stereochemistry of S and S " compounds " reductive cleavage of sulphides, synthetic uses of alkene- and alkyne-thiolates, and thio-Claisen rearrangements nucleophilic displacements at sulphur in disulphides aromatic... 

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