Publication: Specific detection of L-glutamate in food using flow-injection analysis and enzymatic recycling of substrate
Issued Date
2004-08-02
Resource Type
ISSN
00032670
Other identifier(s)
2-s2.0-3142674988
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Mahidol University
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SCOPUS
Bibliographic Citation
Analytica Chimica Acta. Vol.518, No.1-2 (2004), 127-135
Suggested Citation
W. Khampha, J. Yakovleva, D. Isarangkul, S. Wiyakrutta, V. Meevootisom, J. Emnéus Specific detection of L-glutamate in food using flow-injection analysis and enzymatic recycling of substrate. Analytica Chimica Acta. Vol.518, No.1-2 (2004), 127-135. doi:10.1016/j.aca.2004.05.048 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/21169
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Title
Specific detection of L-glutamate in food using flow-injection analysis and enzymatic recycling of substrate
Abstract
A flow injection analysis (FIA) system for specific determination of L-glutamate in food samples based on a bi-enzymatic amplification system has been developed. The content of L-glutamate in the sample was amplified by cycling between L-glutamate dehydrogenase (GlDH) and a novel enzyme, D-phenylglycine aminotransferase (D-PhgAT). In this system, GlDH converts L-glutamate to 2-oxoglutarate with concomitant reduction of NAD+to NADH. D-PhgAT transfers an amino group from D-4-hydroxyphenylglycine to 2-oxoglutarate, thus recycling L-glutamate. Accumulation of NADH in the course of the enzymatic recycling was monitored both by fluorescence and UV absorbance and used for quantification of L-glutamate. The assay was characterized by high long-term stability (at least 70 days) and good reproducibility (within-day and between-day RSDs were 4.3-7.3% and 8.9%). The fluorimetric assay was slightly more sensitive with a L-glutamate detection limit of 0.4 μM and linear range of 2.5-50 μM. The assay was specific for L-glutamate, with recoveries between 95-103% in the presence of 17 different amino acids tested one by one. The method was applied to analysis of real food samples and results were correlated with a commercial Boehringer Mannheim assay kit. © 2004 Elsevier B.V. All rights reserved.