A method for the isolation of the amide nitrogen of glutamine from biological samples for mass spectrometry
1982; Elsevier BV; Volume: 121; Issue: 2 Linguagem: Inglês
10.1016/0003-2697(82)90492-4
ISSN1096-0309
AutoresFarook Jahoor, Alan A. Jackson, Michael Golden,
Tópico(s)Biochemical and Molecular Research
ResumoThe amide nitrogen from l-glutamine has been isolated from an artificial plasma, in a form suitable for mass spectrometry, by a macromodification of the glutaminase reaction. The prior removal of free ammonia was carried out by alkaline aeration. When this was performed at 0°C for 3 h, spontaneous hydrolysis of glutamine was 1.4%. Cross-contamination with nitrogen liberated from the amide group of asparagine can be avoided by preincubation with asparaginase for 2 h and removal of the freed ammonia prior to reacting with glutaminase. Hydrolysis of glutamine during this step is 12%. Measurements of enrichment can be made on samples yielding more than 1 μmol of glutamine amide-derived ammonia.
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