Abstract
Syntheses of various γ-glutamylpeptides were examined taking use of the highly purified γ-glutamylcysteine synthetase from Proteus mirabilis. The accumulation of each peptide was measured after long time incubation, and good formation was observed in the synthesis of peptides of following amino acids, L-cysteine, L-α-aminobutyrate, L-serine, L-homoserine, glycine, L-alanine, L-norvaline, L-lysine, L-threonine, taurine and L-valine. Peptide syntheses were confirmed by analyses of the component amino acids, after hydrolysis of the peptides.
The structure of the glutamylpeptides, especially the peptide-linkage at the γ-carbonyl residue of L-glutamate, was determined by mass spectrometry of the N-trifluoroacetyl methylester derivatives of the glutamylpeptides. Enzymatic synthesis of γ-glutamyl-L-α-aminobutyrate was also confirmed by PMR spectrometry in the comparison with chemically synthesized compound.
