Pivotal Enzyme in Glutamate Metabolism of Poly-γ-Glutamate-Producing Microbes

Life

Makoto Ashiuchi¹  Takashi Yamamoto² 

[1] Graduate School of Integrated Arts and Sciences, Kochi University, Nankoku, Kochi 783-8502, Japan;

关键词: L-glutamate sources;    glutamate racemase;    PGA chirality;    archaea;    bacteria;   

DOI  :  10.3390/life3010181

来源: mdpi

【 摘 要 】

The extremely halophilic archaeon Natrialba aegyptiaca secretes the L-homo type of poly-γ-glutamate (PGA) as an extremolyte. We examined the enzymes involved in glutamate metabolism and verified the presence of L-glutamate dehydrogenases, L-aspartate aminotransferase, and L-glutamate synthase. However, neither glutamate racemase nor D-amino acid aminotransferase activity was detected, suggesting the absence of sources of D-glutamate. In contrast, D-glutamate-rich PGA producers mostly possess such intracellular sources of D-glutamate. The results of our present study indicate that the D-glutamate-anabolic enzyme “glutamate racemase” is pivotal in the biosynthesis of PGA.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.