Comparison of desorption/ionization on silicon (DIOS) time‐of‐flight and liquid chromatography/tandem mass spectrometry for assaying enzyme‐inhibition reactions

Wall, Daniel; Finch, Jeffrey W.; Cohen, Steven A.

doi:10.1002/rcm.1511

Cited by 20 publications

(14 citation statements)

References 22 publications

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“…The LC/MS/MS method resulted in the widest linear dynamic range (1.0-500.0 µM) compared with the DIOS method (5.0-500.0 µM). It can be used for rapid and specific quantification of enzyme-inhibition assays [34].…”

Section: Assays Based On Mass Spectrometric Detectionmentioning

confidence: 99%

Natural Product Inhibitors of Acetylcholinesterase

Hostettmann¹,

Borloz²,

Urbain³

et al. 2006

COC

137

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Various natural products, such as physostigmine, have long been recognized as inhibitors of the enzyme acetylcholinesterase. Since the recent approval of galanthamine for the treatment of Alzheimer's disease by the blockage of acetylcholine degradation, attempts to find other inhibitors of the enzyme have multiplied, leading to promising candidates such as huperzine A. In this review, a listing is presented of natural product inhibitors, both alkaloid and nonalkaloid in origin. These have been isolated from plant, animal and microbial sources. Details of current testing methods on cholinesterases are given, including solution assays and screening techniques by TLC and HPLC.

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Section: Assays Based On Mass Spectrometric Detectionmentioning

confidence: 99%

Natural Product Inhibitors of Acetylcholinesterase

Hostettmann¹,

Borloz²,

Urbain³

et al. 2006

COC

137

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show abstract

“…It is now also applied as a tool for the quantification of low molecular weight compounds of biological interest. Assaying enzyme-inhibition reactions has also been shown using matrix-free laser desorption/ionization process on porous silicon (DIOS) [31,32] and MALDI-MS using a matrix of oxidized carbon nanotubes [33]. Fourier transform mass spectrometry (FTMS) was introduced to couple with MALDI because of its remarkable mass resolution and accuracy.…”

mentioning

confidence: 99%

Monitoring enzyme reaction and screening of inhibitors of acetylcholinesterase by quantitative matrix-assisted laser desorption/ionization fourier transform mass spectrometry

Yao

Wei

et al. 2008

J. Am. Soc. Mass Spectrom.

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A matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS)-based assay was developed for kinetic measurements and inhibitor screening of acetylcholinesterase. Here, FTMS coupled to MALDI was applied to quantitative analysis of choline using the ratio of choline/acetylcholine without the use of additional internal standard, which simplified the experiment. The Michaelis constant (K m ) of acetylcholinesterase (AChE) was determined to be 73.9 mol L Ϫ1 by this approach. For Huperzine A, the linear mixed inhibition of AChE reflected the presence of competitive and noncompetitive components. The half maximal inhibitory concentration (IC 50 ) value of galantamine obtained for AChE was 2.39 mol L Ϫ1 . Inhibitory potentials of Rhizoma Coptidis extracts were identified with the present method. In light of the results the referred extracts as a whole showed inhibitory action against AChE. The use of high-resolution FTMS largely eliminated the interference with the determination of ACh and Ch, produced by the low-mass compounds of chemical libraries for inhibitor screening. The excellent correlation with the reported kinetic parameters confirms that the MS-based assay is both accurate and precise for determining kinetic constants and for identifying enzyme inhibitors. The obvious advantages were demonstrated for quantitative analysis and also high-throughput characterization. This study offers a perspective into the utility of MALDI-FTMS as an alternate quantitative tool for inhibitor screening of

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“…Wall and coworkers employed both a DIOS/MS and an ESI/MS assay scheme for the determination of kinetic parameters of the AC hydrolysis mediated by AChE and studied also the inhibition of this reaction by tacrine. The values obtained from both methods were found to be in good agreement [17]. Shen and colleagues presented a high-throughput approach based on the DIOS/MS system for the screening of potential AChE inhibitors from a compound library reporting a throughput of 4000 samples in a 5-h measurement period [18].…”

Section: Introductionmentioning

confidence: 90%

Screening of acetylcholinesterase inhibitors in snake venom by electrospray mass spectrometry

Liesener

Perchuc²,

Schöni³

et al. 2007

Pure and Applied Chemistry

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An electrospray ionization/mass spectrometry (ESI/MS)-based assay for the determination of acetylcholinesterase (AChE)-inhibiting activity in snake venom was developed. It allows the direct monitoring of the natural AChE substrate acetylcholine (AC) and the respective product choline. The assay scheme was employed in the screening for neurotoxic activity in fractions of the venom of Bothrops moojeni. AChE inhibition was assessed in two fractions. As a positive control, the established AChE inhibitor 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284c51) was used, a dose-response curve for this compound was generated and the IC 50 value for the inhibitor was determined to be 1.60 ± 0.09 × 10 -9 mol L -1 . The dose-response curve was used as "calibration function" for the venom inhibition activity, resulting in BW284c51-equivalent concentrations of 1.76 × 10 -9 mol L -1 and 1.07 × 10 -9 mol L -1 for the two fractions containing activity. The ESI/MS-based assay scheme was validated using the established Ellman reaction. The data obtained using both methods were found to be in good agreement. The ESI/MS-based assay scheme is therefore an attractive alternative to the standard colorimetric assay.

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Comparison of desorption/ionization on silicon (DIOS) time‐of‐flight and liquid chromatography/tandem mass spectrometry for assaying enzyme‐inhibition reactions

Cited by 20 publications

References 22 publications

Natural Product Inhibitors of Acetylcholinesterase

Natural Product Inhibitors of Acetylcholinesterase

Monitoring enzyme reaction and screening of inhibitors of acetylcholinesterase by quantitative matrix-assisted laser desorption/ionization fourier transform mass spectrometry

Screening of acetylcholinesterase inhibitors in snake venom by electrospray mass spectrometry

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