Document Detail

Urinary 2-hydroxy-5-oxoproline, the lactam form of α-ketoglutaramate, is markedly increased in urea cycle disorders.
MedLine Citation:
PMID:  21298421     Owner:  NLM     Status:  MEDLINE    
α-Ketoglutaramate (KGM) is the α-keto acid analogue of glutamine, which exists mostly in equilibrium with a lactam form (2-hydroxy-5-oxoproline) under physiological conditions. KGM was identified in human urine and its concentration quantified by gas chromatography/mass spectrometry (GC/MS). The keto acid was shown to be markedly elevated in urine obtained from patients with primary hyperammonemia due to an inherited metabolic defect in any one of the five enzymes of the urea cycle. Increased urinary KGM was also noted in other patients with primary hyperammonemia, including three patients with a defect resulting in lysinuric protein intolerance and one of two patients with a defect in the ornithine transporter I. These findings indicate disturbances in nitrogen metabolism, most probably at the level of glutamine metabolism in primary hyperammonemia diseases. Urinary KGM levels, however, were not well correlated with secondary hyperammonemia in patients with propionic acidemia or methylmalonic acidemia, possibly as a result, in part, of decreased glutamine levels. In conclusion, the GC/MS procedure has the required lower limit of quantification for analysis of urinary KGM, which is markedly increased in urea cycle disorders and other primary hyperammonemic diseases.
Tomiko Kuhara; Yoshito Inoue; Morimasa Ohse; Boris F Krasnikov; Arthur J L Cooper
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-02-06
Journal Detail:
Title:  Analytical and bioanalytical chemistry     Volume:  400     ISSN:  1618-2650     ISO Abbreviation:  Anal Bioanal Chem     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-05-20     Completed Date:  2011-09-01     Revised Date:  2013-06-30    
Medline Journal Info:
Nlm Unique ID:  101134327     Medline TA:  Anal Bioanal Chem     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  1843-51     Citation Subset:  IM    
Department of Biochemistry, Division of Human Genetics, Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku-gun, Ishikawa, 920 0293, Japan.
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MeSH Terms
Ammonia / blood
Child, Preschool
Gas Chromatography-Mass Spectrometry
Hydroxyproline / urine*
Infant, Newborn
Ketoglutaric Acids / metabolism*
Lactams / metabolism*
Urea Cycle Disorders, Inborn / urine*
Grant Support
Reg. No./Substance:
0/Ketoglutaric Acids; 0/Lactams; 328-50-7/alpha-ketoglutaric acid; 51-35-4/Hydroxyproline; 7664-41-7/Ammonia

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