Identification and Quantification of Neuropeptides in Brain Tissue by Capillary Liquid Chromatography Coupled Off-Line to MALDI-TOF and MALDI-TOF/TOF-MS

Wei, Hui; Nolkrantz, Kerstin; Parkin, Mark C.; Chisolm, Claire N.; O’Callaghan, James P.; Kennedy, Robert T.

doi:10.1021/ac052196x

Cited by 50 publications

(72 citation statements)

References 45 publications

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“…Off-line capillary liquid chromatography was combined with MALDI-TOF MS and TOF/TOF-MS for the identification and quantification of neuropeptides in microwave-fixed rat brain tissue [42]. The effluent was mixed with matrix solution and transferred to a MALDI target plate by pulsed electric field deposition.…”

Section: Peptides and Proteinsmentioning

confidence: 99%

Quantitative matrix-assisted laser desorption/ionization mass spectrometry

Duncan¹,

Röder²,

Hunsucker³

2008

Briefings in Functional Genomics and Proteomics

191

162

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This review summarizes the essential characteristics of matrix-assisted laser desorption/ionization (MALDI) timeof-flight mass spectrometry (TOF MS), especially as they relate to its applications in quantitative analysis. Approaches to quantification by MALDI-TOF MS are presented and published applications are critically reviewed.Keywords: quantification; quantitative analysis; MALDI; mass spectrometry; biomarkers OVERVIEWSince its inception in 1987 [1], matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF MS) has been applied for the analysis of a wide range of biomolecules. Initial applications were almost exclusively for the qualitative analysis of biopolymers because MALDI-TOF MS provided a fast and accurate approach to molecular mass and purity information: Is my material the right mass and is it free from contaminants? Because of the speed of analysis, ease of use, relative low equipment cost, ease of data interpretation and limited potential for cross-contamination between samples/users, MALDI-TOF MS systems were considered walk-up instruments where investigators run their own samples and determine, within minutes, whether they were on the right track with their work.There were, however, two specific areas of application where MALDI-TOF MS was initially viewed as impractical: i.e. the analysis of low mass analytes and quantitative applications. Low mass analysis is complicated by the vast molar excess of the matrix that can swamp any analyte-specific signal in the low m/z region of the spectrum. Quantitative analysis was viewed as implausible because crystallization does not yield a uniform distribution of the analyte and matrix across the target surface and this gives rise to regions where the analyte signal is especially intense relative to other locations on the target surface. MALDI MS was therefore viewed as inherently irreproducible because, for a given amount of analyte loaded onto the target, the measured ion intensity varies.Subsequently, it has been shown that both these perceived limitations can be overcome and quantification can be routine, both for low and high mass analytes. Now, an extensive list of published applications includes quantification of amino acids, lipids, natural products, drugs, polymers, herbicides, metabolites, toxins, oligonucleotides, carbohydrates, peptides and proteins. (Selected applications from these areas are discussed at the end of this review.) Here, we focus on the quantitative applications of MALDI and illustrate applications relating to both low and high-molecular mass analytes. We also discuss the strategies for applying MALDI to relative and absolute quantification. While MALDI is most commonly combined with TOF analysers, other analyser options are possible and applications employing these are also presented. Our aim is not to provide an exhaustive catalogue of published applications, but to discuss the general principles and to illustrate the

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Section: Peptides and Proteinsmentioning

confidence: 99%

Quantitative matrix-assisted laser desorption/ionization mass spectrometry

Duncan¹,

Röder²,

Hunsucker³

2008

Briefings in Functional Genomics and Proteomics

191

162

View full text Add to dashboard Cite

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“…As a complement to ESI MS, capillary LC and MALDI TOF/TOF/TOF combinations were successfully used to identify and quantify neuropeptides (44). In this procedure, the peptide samples were separated on a reversed-phase column and directly spotted onto MALDI target plates or onto prespotted targets with an on-line fraction collector.…”

Section: Discovery Of Novel Endogenous Peptidesmentioning

confidence: 99%

Neuropeptidomics: MS Applied to the Discovery of Novel Peptides from the Brain

Svensson¹,

Sköld²,

Nilsson³

et al. 2007

Anal. Chem.

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Section: Nih-pa Author Manuscriptmentioning

confidence: 99%

“…Therefore, there is a great need for improved sampling methods to increase analyte concentration for neuropeptides. Such sampling methods that could ultimately be applied to in vivo studies would be complemented by the ongoing research towards significant improvements in neuropeptide detection and identification in low microliter volume samples [11][12][13].Microdialysis sampling is a diffusion-based process where a perfusion fluid is passed through an inlet tube and then passed through a semi-permeable membrane with a defined molecular weight cutoff. Analytes being sampled can freely diffuse into the probe.…”

mentioning

confidence: 99%

An in vitro comparison of microdialysis relative recovery of Met- and Leu-enkephalin using cyclodextrins and antibodies as affinity agents

Fletcher

Stenken

2008

Analytica Chimica Acta

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Cyclodextrins and antibodies have been used as affinity agents to improve relative recovery during microdialysis sampling. Two neuropeptides, methionine-enkephalin (ME) and leucine-enkephalin (LE), were chosen to compare the use of cyclodextrins and antibodies as possible affinity agents for improving their relative recovery across polycarbonate and polyethersulfone membranes during in vitro sampling. Cyclodextrins (CD) including β-CD, 2-hydroxypropyl-β-cyclodextrin (2HPβ-CD), and γ-CD gave improvements of relative recovery for both peptides of less than 2-fold as compared to controls. Comparisons of relative recovery between tyrosine-glycine-glycine, tyrosine, and phenylalanine using different cyclodextrins in the perfusion fluid were also obtained. Inclusion of an antibody against met-enkephalin in the microdialysis perfusion fluid resulted in relative recovery increases of up to 2.5-fold. These results show that using antibodies as affinity agents during microdialysis sampling may be more effective agents to improve the relative recovery of these opioid neuropeptides.Keywords microdialysis sampling; neuropeptides; affinity agents; cyclodextrins; antibodies IntroductionNeuropeptides are a class of neurotransmitters that are the most structurally diverse group of neuromodulators [1]. Enkephalins are endogenous opioid neuropeptides that have morphinelike action or pain relief in the body and are readily associated with the neurochemistry of addiction [2]. Enkephalins also play significant roles in mediating body temperature control, food intake, reward mechanisms, and stress [3].Microdialysis sampling has been used for over thirty years for chemical sampling applications in neuroscience, pharmacokinetics, and drug metabolism [4][5][6]. It is by far the most commonly used method for the collection of low molecular weight hydrophilic neurotransmitters, such as acetylcholine, dopamine, and glutamate from mammalian brain with high relative recovery Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptAnal Chim Acta. Author manuscript; available in PMC 2009 July 14. Published in final edited form as:Anal Chim Acta. 2008 July 14; 620(1-2): 170-175. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript [7][8][9]. Despite the successful applications of microdialysis sampling, the main limitations for sampling large neuropeptides are a combination of their low relative recoveries and low basal concentrations. A neuropeptide with a high molecular weight will exhibit a smaller aqueous diffusion coefficient, which directly aff...

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Identification and Quantification of Neuropeptides in Brain Tissue by Capillary Liquid Chromatography Coupled Off-Line to MALDI-TOF and MALDI-TOF/TOF-MS

Cited by 50 publications

References 45 publications

Quantitative matrix-assisted laser desorption/ionization mass spectrometry

Quantitative matrix-assisted laser desorption/ionization mass spectrometry

Neuropeptidomics: MS Applied to the Discovery of Novel Peptides from the Brain

An in vitro comparison of microdialysis relative recovery of Met- and Leu-enkephalin using cyclodextrins and antibodies as affinity agents

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