Isao Matsubara

Gas chromatographic determination of the optical purities of amino acids using N-trifluoroacetyl menthyl esters

Abstract Nineteen α-amino acids and one β-amino acid were resolved as their N-TFA menthyl esters by gas-liquid chromatography. Neutral and basic amino acids were well resolved on some conventional packed columns. For the complete resolution of acidic amino acids, a capillary column was used. The results of the applications to some biochemical substances showed that this method is of value for practical usage. The mechanism of the resolution was also investigated and showed that the difference between the derivatives of the enantiomeric pairs in the ability to form intermolecular hydrogen bond contributes essentially to the resolution.

The Mechanism of the Formation of γ-Glutamylpeptides during l-Glutamic Acid Fermentation Contributed Solely by γ-Glutamyltranspeptidase

The enzyme of Corynebacterium glutamicum that catalyzes the formation of various γ-L(D)-glutamylpeptides by the reversal of hydrolysis was found to be γ-glutamyltranspeptidase. The enzyme catalyzed γ-l(d)-glutamyl transfer reaction from various γ-L(D)-glutamyl- peptides including glutathione. The susceptibility of D-isomers was 17% of that of l-isomers. Many kinds of α-l-amino acids and peptides such as γ-l-GIu-l-GIu could be γ-glutamyl acceptors. These findings offered full explanation on the formation of γ-l-glutamylpeptides in the l-glutamic acid fermentation. In the supposed mechanism, γ-l-GIu-l-GIu is formed mainly by the reversal of hydrolysis from l-glutamic acid being richly produced by the bacteria. The other four minor peptides are formed by the γ-glutamyltranspeptidatkm from γ-l-GIu-l-Glu to some α-l-amino acids and to γ-l-GIu-l-GIu itself in the broths. The enzyme was found to be widely distributed among bacteria, especially in some strains of Corynebacterium, Bacillus, Erwinea, Serratia, Pseu...