Formation of disulphide bonds in the reaction of SH group‐containing amino acids with trimethylamine N‐oxide

Abstract
Two amino acids containing SH group (cysteine and homocysteine)+trimethylamine N‐oxide systems were studied by FTIR and 1H NMR spectroscopy. This study demonstrates that cysteine and homocysteine ethylesters react with trimethylamine N‐oxide. Immediately after mixing, SH⋯ON ⇋ S⋯H+ ON hydrogen bonds with large proton polarizability are formed. Then a reaction proceeds resulting in the formation of corresponding disulphides. Trimethylamine N‐oxide is present in biological systems. Thus, our results suggest that trimethylamine N‐oxide may play a regulatory role in S‐S bond formation in enzymes and other proteins.