(1) A brief method for the characterization of carboxyl-terminal amino acids in peptides and proteins was investigated.
(2) Several new amino acid hydrazides were synthesized.
(3) Soveral di- and tri-peptides were hydrazinolyzed and identified their carboxylterminal amino acid.
(4) The method was applied to beef insulin and tyrocidin for the demonstration of its applicability.
1. Raney nickel catalyst treated with optically active glutamic acid has the property of catalyzing the hydrogenation of carbonyl compounds asymmetrically with high reproducibility and efficiency.
2. Excellent results were obtained in the hydrogenation of methyl acetoacetate to optically active methyl 2-hydroxybutyrate in the presence of Raney nickel catalyst treated with l- or d-glutamic acid.
3. The capacity for asymmetric hydrogenation was strongly dependent upon the pH of the modifying solution. The highest capacity was obtained when modifying solutions were adjusted to pH 4.8∼5.5.
4. With elevation of the temperature of the modifying process, the asymmetric capacity of the catalyst decreased markedly, nearly disappearing at 60°C, and yielding products with reverse optical rotation above 80°C.
5. The asymmetric capacity was independent of the concentration of the modifying solution within the range of 6 to 0.0625%.
6. Hydrogenation in the presence of catalyst modified with d-glutamic acid yielded a product with reverse optical rotation to that obtained when l-glutamic acid was used.
7. Asymmetric yield of the reducing product of methyl acetoacetate by the catalyst treated with Glu was varied with the relative amount of the substrate and the catalyst.
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
A new method is described for the synthesis of threonine from acetaldehyde and copper glycinate. This method gives a mixture of allo-threonine and threonine in a high yield (64%).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.