Hydrazine cleaves amide bonds to form acylhydrazides according to the general mechanism
of nucleophilic acyl substitution discussed in Chapter 20:

This reaction forms the basis of one method of terminal residue analysis. A peptide is treated with excess hydrazine in order to cleave all the peptide linkages. One of the terminal amino acids is cleaved as the free amino acid and identified; all the other amino acid residues are converted to acylhydrazides. Which amino acid is identified by hydrazinolysis, the N terminus or the C terminus?

Transcribed Image Text:

RCNHR HNNH2 RCNHNH2 R'NH2 Acylhydrazide Amine Amide Hydrazine