4324 Pyroglutamic acid Pyroglutamic acid, or 5-oxoproline, is a cyclized derivative of L-glutamic acid. It is an uncommon amino acid derivative in which the free amino group of glutamic acid cyclizes to form a lactam. It is formed nonenzymatically from glutamate, glutamine, and gamma-glutamylated peptides, but it can also be produced by the action of gamma-glutamylcyclotransferase on an L-amino acid. Elevated blood levels may be associated with problems of glutamine or glutathione metabolism. This compound is found in substantial amounts in brain tissue and other tissue in bound form, especially skin. Also present in plant tissues. It is sold, over the counter, as a smart drug for improving blood circulation in the brain. 98-79-3 7405 C5H7NO3 White powder. 158°C (316.4°F) 476.0 mg/mL at 13°C 5-Oxoprolinuria develops in moderate to severe cases of glutathione synthetase deficiency. The deficiency in glutathione synthetase leads to the accumulation of γ-glutamylcysteine, which is converted into 5-oxoproline by the action of γ-glutamyl cyclotransferase. The excessive formation of 5-oxoproline exceeds the capacity of 5-oxoprolinase, leading to accumulation of 5-oxoproline in body fluids causing metabolic acidosis and 5-oxoprolinuria. 5-Oxoproline accumulation is thought to be the cause of metabolic acidosis in Hawkinsinuria. 5-Oxoprolinase deficiency also leads to decreased conversion of 5-oxoproline to glutamate, resulting in elevated levels of 5-oxoproline in body fluids. 5-Oxoprolinuria has also been described in patients with urea cycle defects, such as ornithine transcarbamoylase deficiency or homocystinuria. In nephropathic cystinosis 5-oxoprolinuria may occur because of secondary impairment of the γ-glutamyl cycle resulting from decreased availability of free cysteine and can be corrected through cysteamine therapy. Transient 5-oxoprolinuria of unknown cause has been reported in very preterm infants. Limited availability of glycine in malnutrition and pregnancy as well as increased turnover of collagen, fibrinogen and other proteins containing considerable amounts of 5-oxoproline in patients with severe burns or Stevens-Johnson syndrome may lead to 5-oxoprolinuria. In addition, certain drugs, such as paracetamol, vigabatrin or some antibiotics (flucloxacillin, netimicin), are known to induce 5-oxoprolinuria, probably through interaction with the γ-glutamyl cycle. Particular infant formulas and tomato juice may contain modified proteins with increased content of 5-oxoproline. (T527) 5-Oxoproline is part of the glutathione metabolism pathway. Degradation of glutathione is initiated by γ-glutamyl transpeptidase, which catalyses the transfer of its γ-glutamyl-group to acceptors. The γ-glutamyl residues are substrates of the γ-glutamyl-cyclotransferase, which converts them to 5-oxoproline and the corresponding amino acids. Conversion of 5-oxoproline to glutamate is catalysed by 5-oxoprolinase. (T527) No indication of carcinogenicity to humans (not listed by IARC). This is an endogenously produced metabolite found in the human body. It is used in metabolic reactions, catabolic reactions or waste generation. Chronically high levels of pyroglutamic acid are associated with at least 5 inborn errors of metabolism including: 5-Oxoprolinuria, 5-oxoprolinase deficiency, Glutathione Synthetase Deficiency, Hawkinsinuria and Propionic acidemia. Patients with the moderate variant of glutathione synthetase deficiency usually present during the neonatal period with severe and chronic metabolic acidosis, mild to moderate haemolytic anaemia, jaundice and 5-oxoprolinuria. After the neonatal period, the condition usually stabilises, but patients may become critically ill during infections owing to pronounced acidosis and electrolyte imbalances. Several patients have died during such episodes. In addition to the symptoms mentioned above, patients with severe GS deficiency develop progressive CNS symptoms, e.g. mental retardation, seizures, spasticity, ataxia and intention tremor. In addition, some patients suffer from recurrent severe bacterial infections, which is probably due to defective granulocyte function. Hawkinsinuria is characterised by failure to thrive and metabolic acidosis in infancy. After the 1st year of life the condition appears to be asymptomatic. Early weaning from breastfeeding seems to precipitate the disease; the condition may be asymptomatic in breastfed infants. 5-Oxoprolinase Deficiency: Up to now, eight patients in six different families have been described. The clinical symptoms are inconstant and very heterogeneous, including renal stone formation, enterocolitis, neonatal hypoglycaemia, microcytic anaemia, microcephaly and mental retardation. It remains to be established wheter symptoms in identified patients are merely a coincidence. (T527) Glutathione Synthetase Deficiency: The clinical management of GS deficient patients is aimed at correction of acidosis, prevention of haemolytic crises and support of endogenous defence against reactive oxygen species (ROS). In the neonatal period, correction of metabolic acidosis, electrolyte imbalances, treatment of anaemia and excessive hyperbilirubinaemia are of crucial importance. Correction of acidosis can be reached through bicarbonate, citrate or tris-hydroxymethyl aminomethane (THAM). Doses of up to 10 mmol/kg/day, or even higher in episodes of acute infections, may be required. Repeated blood transfusions may be necessary in patients with massive haemolysis. Drugs and foods known to precipitate haemolytic crises in patients with glucose- 6-phosphatase dehydrogenase deficiency should be avoided. Successful treatment with erythropoietin has been reported in one patient. Early supplementation with vitamin E and vitamin C are thought to replenish the lack of GSH as a scavenger of free radicals. Recommended doses are 10 mg/kg/day for vitamin E and 100 mg/kg/day for vitamin C. A longterm follow-up study of 28 patients suggested that early supplementation with both vitamins may prevent CNS damage and improve the long-term clinical outcome in GS-deficient patients. The value of N-acetylcysteine, which is known to protect cells from oxidative stress in vitro, in the treatment of GS deficiency is controversial. It was suggested that the low intracellular GSH concentrations and cysteine availabilty might be increased by N-acetylcysteine. However, supplementation with N-acetylcysteine should not be recommended, because it was shown at least in cultured fibroblasts that patients with GS deficiency accumulate cysteine, which is known to be neurotoxic in excessive amounts. A therapeutic trial with orally administered GSH showed no lasting benefit in two patients with GS deficiency. GSH esters, lipid-soluble preparations which are easily transported into cells where they are converted into GSH, have been tried in animal models of GSH deficiency and in two patients with GS deficiency. However, associated toxic effects due to production of alcohols as a by-product during hydrolysis to release GSH make them of limited use. In vitro studies have shown that addition of S-acetylglutathione to the medium of cultured fibroblasts from patients with GS deficiency normalised intracellular GSH content. Owing to the rarity of the disease and the heterogeneity of the clinical condition the prognosis for individual patients is difficult to predict. Early diagnosis, correction of acidosis and early supplementation with vitamin E and vitamin C appear to be the most important factors regarding the survival and the long-term outcome. Hawkinsinuria: Symptoms in infancy respond to a return to breastfeeding or a diet restricted in tyrosine and phenylalanine along with vitamin C supplementation. The condition is asymptomatic after the 1st year of life, and affected infants are reported to have developed normally. 5-Oxoprolinase Deficiency: No specific treatment has been proposed or tried. (T527) 2014-08-29T06:11:12Z 2026-05-14T17:48:02Z Pyroglutamic acid C01879 18183 CPD-589 DB03088 PCA true OC(=O)[C@@H]1CCC(=O)N1 C5H7NO3 InChI=1S/C5H7NO3/c7-4-2-1-3(6-4)5(8)9/h3H,1-2H2,(H,6,7)(H,8,9)/t3-/m0/s1 ODHCTXKNWHHXJC-VKHMYHEASA-N 129.114 129.042593095 Endogenous Solid HMDB00267 CHEMBL397976 7127 <p>John G. Black, Ian R. Scott, &#8220;Pyroglutamic acid esters, their synthesis and use in topical products.&#8221; U.S. Patent US4774255, issued December, 1974.</p> CHEM003230 DTXSID6046260 (2S)-5-oxopyrrolidine-2-carboxylic acid 66.4 28.0878 11.55635110215903 1 3 2 3.613354339229633 -2.2244398721602403 -1 1 -1.01 0.07 1.51e+02 g/l