Analysis of glutamine, glutamate, pyroglutamate, and GABA in cerebrospinal fluid using ion pairing HPLC with positive electrospray LC/MS/MS

Eckstein, James A.; Ammerman, Gina M.; Reveles, Jessica M.; Ackermann, Bradley L.

doi:10.1016/j.jneumeth.2008.02.019

Cited by 94 publications

(64 citation statements)

References 32 publications

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“…S2 in the supplemental material), which is similar to that of the most sensitive HPLC-tandem mass spectrometry (HPLC-MS/MS) assay (7,11). The linear range of the assay extended across 3 orders of magnitude (0.0001 to 0.1 g/ml Gln) (see Fig.…”

mentioning

confidence: 59%

Bacterial Whole-Cell Biosensor for Glutamine with Applications for Quantifying and Visualizing Glutamine in Plants

Tessaro

Soliman

Raizada

2012

Appl Environ Microbiol

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A whole-cell biosensor for glutamine (GlnLux) was constructed by transforming an Escherichia coli glutamine (Gln) auxotroph with a constitutive lux reporter gene. Measurements of Gln in plant extracts using GlnLux correlated with quantification using high-performance liquid chromatography (Spearman's r ‫؍‬ 0.95). GlnLux permitted charge-coupled-device (CCD) imaging of Gln from whole plant organs.

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mentioning

confidence: 59%

Bacterial Whole-Cell Biosensor for Glutamine with Applications for Quantifying and Visualizing Glutamine in Plants

Tessaro

Soliman

Raizada

2012

Appl Environ Microbiol

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“…9,20,21 Therefore, some analysis techniques that eliminate the need for derivatization procedures have been established, such as HPLC-mass spectrometry (HPLC-MS) and HPLC-evaporative light scattering detection (HPLC-ELSD) with using an ion-pairing reagent such as trifluoroacetic acid, tetrabutylammonium hydroxide, heptafluorobutyric acid and perfluorinated acid and so on. [22][23][24] Addition of ion-pair reagents to mobile phase improves separation of underivatized amino acids on a reverse-phase silica-based C8 or C18 columns. 20,23,25,26 They also increase the MS signal of amino acids and improve peak shape.…”

Section: Introductionmentioning

confidence: 99%

“…20,23,25,26 They also increase the MS signal of amino acids and improve peak shape. However, ion-pair reagents frequently affect assay durability, 22 increase the retention times of amino acids 20 and decrease the sensitivity of the MS detector. 27 All these problems limited the application of the above methods.…”

Section: Introductionmentioning

confidence: 99%

Determination of Free Amino Acids in Isatidis Radix By HILIC-UPLC-MS/MS

Pan¹,

Jin²,

Li³

et al. 2014

Bulletin of the Korean Chemical Society

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A rapid, accurate and precise method for the determination of 22 amino acids in Isatidis Radix by Hydrophilic Interaction Ultra-High-Performance Liquid Chromatography Coupled with Triple-Quadrupole Mass Spectrometry (HILIC-UPLC-MS/MS) was established. Chromatographic separation was carried out on a Acquity UPLC BEH Amide column (2.1 mm × 100 mm, 1.7 m) with gradient elution of acetonitrile (containing 0.05% formic acid and 2 mM ammonium formate) and water (containing 0.15% formic acid and 10 mM ammonium formate) at a flow rate of 0.4 mL/min; Waters Xevo TM TQ worked in multiple reaction monitoring mode. All components were separated in 17 min. All calibration curves were linear (R 2 > 0.991) over the tested ranges. The limits of detection (LOD) and limits of quantitation (LOQ) for these compounds were 0.21-79.55 and 0.72-294.23 ng/mL, respectively. The average recoveries were in the range of 93.75-104.16% with RSD value less than 6.56%. Therefore, this method could be an alternative assay for the determination of 22 amino acids in Isatidis Radix due to its rapidness, sensitivity, less sample and solvent consumption.

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“…연구자들은 GABA가 풍부한 기능성 식품을 만들기 위하 여 녹차 [8], 현미 [9], 보리 [10], 밀 [11], 홍국미 [12] 등 다양 한 종류의 식물을 유산균 발효를 통하여 GABA생산에 관한 연구를 수행하였다. 그러나 이러한 유산균을 이용한 GABA 의 생산증진 방법은 유산균의 대사과정을 이용하기 때문에 GABA의 생산성에 한계가 있다 [13]. 유산균을 이용한 GABA의 생산성의 한계를 극복하기 위 하여 GABA의 생산능력을 보유한 재조합 미생물의 개발에 관한 연구 또한 진행되고 있다 [14][15][16].…”

Section: Introductionunclassified

“…일반적으로 GABA를 합성하는 공정은 glutamic acid decarboxylase (GAD)를 이용 하여 glutamate를 탈 탄산화시켜 GABA로 만드는 과정이다. 이 전환반응은 보조인자인 prydoxal-5'-phosphate (PLP)를 필 요로 하며, GAD는 65 kDa (GAD 65), 67 kDa (GAD 67) 두 개의 isoform이 존재한다 [17][18][19] [13,24,25]. 이동상은 0.05% TFA/ DW과 0.05% TFA/ACN를 이용하였으며, 분석용 컬럼은 XTerra RP 18 (5 µL, 4.6×100 mm)을 사용하고 400 nm에서 0.7 mL/min의 flow rate 조건에서 분석하였다.…”

Section: Introductionunclassified

Effects and Optimization of Gamma-Amino Butyric Acid (GABA) Production Process using Glutamate Decarboxylase (GAD)

김의진¹,

이중헌²

2014

KSBB Journal

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pH controlled batch reactor and bubble column reactors have been developed in this research. They were used to produce high concentration of GABA and to determine optimal pH for GABA production. Glutamate decarboxylase (GAD) was isolated from recombinant E. coli and used for GABA production from monosodium glutamate (MSG). pH control was inevitable because the pH increased with MSG consumption. GAD showed highest activity at acidic conditions at pH 5.5 but the optimal pH for GABA production was pH 6.0. When 1.5 mole of MSG was used as reactant, the 1.05 mole of GABA was produced after 10 hrs batch reaction. Using bubble column reactors, 80 % of MSG was converted to GABA for 6 hrs reaction and 1.2 mole of GABA was produced.

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Analysis of glutamine, glutamate, pyroglutamate, and GABA in cerebrospinal fluid using ion pairing HPLC with positive electrospray LC/MS/MS

Cited by 94 publications

References 32 publications

Bacterial Whole-Cell Biosensor for Glutamine with Applications for Quantifying and Visualizing Glutamine in Plants

Bacterial Whole-Cell Biosensor for Glutamine with Applications for Quantifying and Visualizing Glutamine in Plants

Determination of Free Amino Acids in Isatidis Radix By HILIC-UPLC-MS/MS

Effects and Optimization of Gamma-Amino Butyric Acid (GABA) Production Process using Glutamate Decarboxylase (GAD)

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