FIELD: chemistry.
SUBSTANCE: invention relates to a method for chemical conversion of a peptide chain into a peptide thioether. A -C(=X)-R1 group is incorporated into a thiol group of a cysteine residue and the obtained peptide then reacts in an organic solvent with a compound having a substituted group of formula: NH-C(=Y)NHR3, and a -NH-C(=Y)NHR3 group binds in an addition reaction with the carboxyl group of the peptide bond at the N-terminal side of the cysteine residue, through which the peptide bond is broken and the peptide moiety at the C-terminal end is cut off. When the obtained peptide chain, having a -NH-C(=Y)NHR3 group, reacts with thiol in a buffer solution, a thiol exchange reaction occurs, specifically the thiol group of the thiol compound binds with the carbon of the carbonyl to which the -NH-C(=Y)NHR3 was bound, thereby removing the -NH-C(=Y)NHR3 group.
EFFECT: achieving conversion to peptide thioether.
14 cl, 4 ex
