Possible Interaction: Pyrrolidonecarboxylic Acid and Glutamic Acid

“Since glutamine and glutamic acid are known to undergo cyclization to pyroglutamic acid , the 22-fold reduction might be the actual reduction in the levels of glutamine and/or glutamic acid—both known to be cancer-related.”

“ Oxoproline (Oxo) provides by glutamic acid production an increase of intracellular folic acid trapping.”

“The inability of aminopeptidase M to degrade the peptide and the presence of glutamic acid in the hydrolysate suggested N-terminal blocking by pyroglutamic acid.”

“The results showed a competitive inhibition of the high affinity transport of glutamic acid by L-pyroglutamic acid in vitro with no effect on the uptake of gamma-aminobutyric acid (GABA).”

“Experiments using doubly labelled mixtures of PCA and … acid, others testing competition for incorporation between PCA … glutamic acid , and the use of an enzyme preparation in which decyclization is inhibited by mercaptoethanol, demonstrated that PCA cannot be incorporated directly into tRNA, but must first be converted to glutamic acid.”

“Since Glu in aqueous solutions is partly transformed into pyroglutamic acid (pGlu; 5-oxo-proline) at higher temperatures and storage [l-3], there is thus the potential risk that this intramolecular cyclization product may be formed in various amounts in parenteral amino acid solutions.”