An Improvement of the Hydrazine Method for Determination of C-Terminal Amino-acids

Abstract

HITHERTO, investigators using the hydrazine method of Akabori and co-workers¹ found it necessary to treat the peptides or protein with anhydrous hydrazine at not less than 100° for about 10 hr. in order to break all peptide bonds^2–4. This severe treatment causes complete decomposition of cysteine, cystine and poor yields of arginine, aspartic acid and glutamic acid, with the result that they cannot be determined satisfactorily as C-terminal amino-acids. It is now shown that by the addition of an acid catalyst it is possible to decompose peptides under much milder conditions so that all the common amino-acids can be recovered in fair yield.