Discovery of the cellular benefits for synthesizing kynurenic acid
Kazuto Ohashi 1, Romanas Chaleckis 2, 3, Masak Takaine 1, 2, Craig E. Wheelock 2, 3, Satoshi Yoshida 1, 2
(1. IMCR, Gunma University 2. GIAR, Gunma University 3. Department of Medical Biochemistry and Biophysics, Karolinska Institutet)
Kynurenic acid (KA) is a tryptophan (Trp) metabolite that is synthesized in a branch of kynurenine pathway. Although KA synthesis is evolutionarily conserved from bacteria to humans, the cellular benefits of synthesizing KA are unclear. In this study, we constructed a yeast mutant defective in KA synthesis and investigated the mutant in detail to define the cellular function of KA. We found that the mutant exhibited no apparent defect in cell growth or viability but showed hyper sensitivity to excess Trp. Our results strongly indicate that KA synthesis is important for detoxification of excess Trp and KA is a safe waste yielded as a consequence of Trp degradation.
Kynurenine aminotransferase activity of Aro8/Aro9 engage tryptophan degradation by producing kynurenic acid in Saccharomyces cerevisiae
Kazuto Ohashi, Romanas Chaleckis, Masak Takaine, Craig E. Wheelock, and Satoshi Yoshida Scientific Reports 7, 12180 (2017)