Hydrazinolysis of Peptides and Proteins. II. Fundamental Studies on the Determination of the Carboxyl-ends of Proteins

Abstract

Abstract 1. Fundamental experiments on the hydrazinolysis method, a method for characterization of C-terminal amino acids of proteins, were carried out. 2. Amino acids were found to decompose to various extents by heating with anhydrous hydrazine. 3. Amino acid hydrazides were hydrolysed about 1% or less by heating with anhydrous hydrazine (ca. 99%) for ten hours. Hydrolyses of them in neutral and slightly acidic solutions at room temperature are negligible, but in alkaline solution the extent of hydrolyses are somewhat greater though less than 0.2% in five hours in 1% bicarbonate solution. 4. Procedures for separating free amino acids from amino acid hydrazides as DNP-derivatives with or without treatment of iso-valeraldehyde prior to dinitrophenylation were reinvestigated thoroughly. 5. Some experiments on the hydrazino-lyses of peptides were done. 6. Fundamental investigations of the characterization of the mode of linkage of monoaminodicarboxylic acids in peptide chains by the hydrazinolysis method indicate its availability. 7. Standard methods for quantitative estimation of C-terminal amino acids or proteins are established based upon the results obtained by the present investigation. 8. Brief consideration on the mechanism of the hydrazinolysis was described and the scope of this method was discussed in conection with that of the carboxypeptidase method