Specific detection of L-glutamate in food using flow-injection analysis and enzymatic recycling of substrate

Khampha, WanidaLund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH (författare)

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 (GIDH) and a novel enzyme, D-phenylglycine aminotransferase (D-PhgAT). In this system, GIDH 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 muM and linear range of 2.5-50 muM. 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. (C) 2004 Elsevier B.V. All rights reserved.

Yakovleva, JuliaLund University,Lunds universitet,Muskelbiologi,Forskargrupper vid Lunds universitet,Muscle Biology,Lund University Research Groups(Swepub:lu)anal-jya (författare)
Isarangkul, D (författare)
Wiyakrutta, S (författare)
Meevootisom, V (författare)
Emnéus, JennyLund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)je5703em (författare)
Centrum för analys och syntesKemiska institutionen (creator_code:org_t)

Ingår i:Analytica Chimica Acta: Elsevier BV518:1-2, s. 127-1351873-43240003-2670

Av författaren/redakt...: Khampha, Wanida; Yakovleva, Julia; Isarangkul, D; Wiyakrutta, S; Meevootisom, V; Emnéus, Jenny

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