Abstract
Five γ-glutamylpeptides were isolated from the L-glutamic acid fermentation broths using Corynebacterium glutamicum, and were identified as γ-L-glutamyl-L-glutamic acid, γ-L-glutamyl-L-glutamine, γ-L-glutamyl-L-valine, γ-L-glutamyl-L-leucine, and γ-L-glutamyl-γ-L-glutamyl-L-glutamic acid, respectively. γ-L-Glutamyl-L-glutamine and the tripeptide are new compounds found in fermentation. It was suggested that these peptides were synthesized by the bacteria. The studies on the crystallization of L-glutamic acid revealed that γ-L-glutamyl-L-glutamic acid was the essential compound that affected the crystallization. More than 0.5% existence of the peptide lowered the crystallization rate, and more than 1.0% existence caused the change of morphological tendency of the crystallization, α-form to β-form. The other peptides did not show any actions to the crystallization by themselves, but when they coexisted with γ-L-glutamyl-L-glutamic acid, they enhanced the action of the peptide.
