Description | There are two forms of glutamic acid found in nature: L-glutamic acid and D-glutamic acid. D-glutamic acid, is not endogenously produced in higher mammals. It is found naturally primarily in the cell walls of certain bacteria. D-glutamate is also present in certain foods e.g., soybeans and also arises from the turnover of the intestinal tract microflora, whose cell walls contain significant D-glutamate. Unlike other D-amino acids, D-glutamate is not oxidized by the D-amino acid oxidases, and therefore this detoxification pathway is not available for handling D-glutamate. Likewise, D-glutamic acid, when ingested, largely escapes most deamination reactions (unlike the L-counterpart). Free D-glutamate is found in mammalian tissue at surprisingly high levels, with D-glutamate accounting for 9% of the total glutamate present in liver. D-glutamate is the most potent natural inhibitor of glutathione synthesis identified to date and this may account for its localization to the liver, since circulating D-glutamate may alter redox stabiity (PMID 11158923 ). Certain eels are known to use D-glutamic acid as a phermone for chemical communication. D-Glutamic acid has been found to be a metabolite of Lactobacillus (PMID: 22754309 ). |
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