D-Pyroglutamic acid

D-Pyroglutamic acid, also known as 5-oxo-D-proline, is a metabolite of D-glutamate. It is formed from D-glutamate by D-glutamate cyclase. The levels of D-pyroglutamic acid are increased in the urine of patients with nascent metabolic syndrome and the plasma of patients with end-stage renal disease.

white to light yellow crystal powder.

D-pyroglutamic acid is formed by the dehydration between the α-NH2 group and the γ-hydroxyl group of glutamic acid to form an intramolecular amide bond; it can also be formed by the loss of an amide group in the glutamine molecule.

Serves as a building block in the synthesis of diphthamide.

ChEBI: D-Pyroglutamic acid is the D-enantiomer of 5-oxoproline. It has a role as a metabolite. It is a D-proline derivative and a 5-oxoproline. It is a conjugate acid of a 5-oxo-D-prolinate. It is an enantiomer of a 5-oxo-L-proline.

D-Pyroglutamic acid (PCA) is a cyclic derivative of glutamic acid, physiologically present in mammalian tissues. It has been shown that PCA releases GABA from the cerebral cortex and displays anti-anxiety effects in a simple approach-avoidance conflict situation in the rat. In clinical pharmacology experiments, PCA significantly shortens the plasma half-life of ethanol during acute intoxication.

Purify R-pyroglutamic acid by dissolving it in H2O, filtering, passing the filtrate through Dowex 50 (H+ form), washing with H2O, pooling washings, evaporating, removing H2O azeotropically with Me2CO and *C6H6, washing the residue with Et2O and recrystallising from EtOH/pet ether. [Pradeller et al. Collect Czech Chem Commun 42 79, 80 1977, Beilstein 22/6 V 7.]

1. Ariyoshi, M., Katane, M., Hamase, K., et al. D-Glutamate is metabolized in the heart mitochondria. Sci. Rep. 7, 43911 (2017). DOI:10.1038/srep43911
2. Shim, K., Gulhar, R., and Jialal, I. Exploratory metabolomics of nascent metabolic syndrome. J. Diabetes Complications 33(3), 212-216 (2019). DOI:10.1016/j.jdiacomp.2018.12.002
3. Palekar AG, et al. Accumulation of 50oxo-L-proline and 5-oxo-D-proline in the blood plasma in end stage renal disease. Biochem Med. 1975 Nov;14(3):339-45. DOI:10.1016/0006-2944(75)90052-6
4. D-Pyroglutamic Acid Production from L-Glutamic Acid by Successive Racemization, Resolution and Dehydration. DOI:10.6967/JCICE.200003.0177