Use of 2,2′-dithiobis(5-nitropyridine) for the heterodimerization of cysteine containing peptides. Introduction of the 5-nitro-2-pyridinesulfenyl group

2,2′-Dithiobis(5-nitropyridine) has proven to be a suitable reagent for the activation of the thiol function of cysteine in peptides and subsequent asymmetric disulfide formation. The utility of this reagent is tested in the preparation of de novo designed cytochrome model heterodimeric 62-mer peptides.