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Identification of phenylbutyrylglutamine, a new metabolite of phenylbutyrate metabolism in humans
Author(s) -
Comte Blandine,
Kasumov Takhar,
Pierce Bradley A.,
Puchowicz Michelle A.,
Scott MaryEllen,
Dahms Williams,
Kerr Douglas,
Nissim Itzhak,
Brunengraber Henri
Publication year - 2002
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.316
Subject(s) - phenylbutyrate , chemistry , metabolite , urine , metabolomics , orotic acid , excretion , biochemistry , metabolism , pharmacology , chromatography , medicine
Phenylbutyrate is used in humans for treating inborn errors of ureagenesis, certain forms of cancer, cystic fibrosis and thalassemia. The known metabolism of phenylbutyrate leads to phenylacetylglutamine, which is excreted in urine. We have identified phenylbutyrylglutamine as a new metabolite of phenylbutyrate in human plasma and urine. We describe the synthesis of phenylbutyrylglutamine and its assay by gas chromatography/mass spectrometry as a tert ‐butyldimethylsilyl or methyl derivative, using standards of [ 2 H 5 ]phenylbutyrylglutamine and phenylpropionylglutamine. After administration of phenylbutyrate to normal humans, the cumulative urinary excretion of phenylacetate, phenylbutyrate, phenylacetylglutamine and phenylbutyrylglutamine amounts to about half of the dose of phenylbutyrate. Thus, additional metabolites of phenylbutyrate are yet to be identified. Copyright © 2002 John Wiley & Sons, Ltd.