The sonolytic hydrolysis of
peptides with addition of phenolic
reagents to aqueous solutions is described. Sonolysis of an aqueous
solution of
peptides to which
catechol (o-dihydroxybenzene) had been added resulted in hydrolytic products reflecting the amino acid sequence without any side reactions, while sonolysis without any additives resulted in oxidation analytes and degradation products caused by side reactions. Although the use of additives such as
resorcinol (m-dihydroxybenzene),
hydroquinone (p-dihydroxybenzene) and
phenol was also effective in producing sequence related products, several degradation products were produced by side reactions. A characteristic of the sonolysis of
peptides is that the N-terminal side of
proline, Xxx-Pro, is more susceptible than other
amino acid residues to the process. This characteristic of sonolysis is superior to that of
acid hydrolysis in which cleavage at the C-terminal side of
proline, Pro-Xxx is difficult, and where
dehydration products result due to side reactions.