ISSN:
1076-5174
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A gas chromatographic/mass spectrometric (GC/MS) method has been developed for the precise and accurate analysis of high enrichment (1-10 mol.% excess) and very low enrichment (0.005-0.12 mol.% excess) 2H5-labelled phenylalanine. Tracer enrichment in free phenylalanine was measured by GC/electron impact MS analysis of the tert-butyldimethylsilyl (TBDMS) derivative. The measurement of very low tracer enrichment, typical of that found in protein hydrolysates, was accomplished by careful control of sample yield during preparation and analysis of the TBDMS derivative of purified β-phenylethylamine, produced by enzymatic decarboxylation and solvent extraction. The new method was illustrated by measurement of albumin synthesis in healthy patients using a rapid protocol which showed good patient acceptability and was straightforward to manage in the clinical setting. The mean (SEM) albumin fractional synthetic rate was 9.54% (0.81%) per day, in agreement with previous studies that used more complex clinical protocols and analytical procedures. Use of the same derivative for analysis of amino acid precursor and protein samples facilitated consecutive analysis on the same instrument without interruption, permitting rapid feedback of results to the clinician and the possibility of using the method in intervention studies. The method should prove useful in the study of the synthetic rate of other proteins and mixed tissue protein, which will help our understanding and management of protein metabolism in health and disease. The possibility of extending the use of multiple-atom tracers combined with GC/MS analysis to other substrate metabolism studies was identified.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jms.1190300917
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