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Wu J, Huang T. Peak identification in capillary isoelectric focusing using the concept of relative peak position as determined by two isoelectric point markers. Electrophoresis 2006; 27:3584-90. [PMID: 16927345 DOI: 10.1002/elps.200500889] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In CIEF analysis, sample peaks can be identified by their relative peak positions (RPP) that are determined using only two internal pI markers. The two internal pI marker peaks should bracket, as close as possible, the sample peaks. The RPP values of the sample peaks are then calculated using the pI values, peak positions of the two pI markers, and peak position of the sample. Use of this method can effectively compensate for pH gradient distortions that often occur as a result of salts. Also, as shown by the results of this paper, regardless of the linearity of the pH gradient established by the given carrier ampholytes, sample peaks can be identified within an SD of 0.1 pH unit in RPP (<2% RSD) as long as the sample is run using the same carrier ampholytes and maintaining salt concentrations in the range of 0-15 mM.
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Affiliation(s)
- Jiaqi Wu
- Convergent Bioscience Ltd., Toronto, Ontario, Canada.
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Huang YF, Huang CC, Hu CC, Chang HT. Capillary electrophoresis-based separation techniques for the analysis of proteins. Electrophoresis 2006; 27:3503-22. [PMID: 16927348 DOI: 10.1002/elps.200600100] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CE offers the advantages of high speed, great efficiency, as well as the requirement of minimum amounts of sample and buffer for the analysis of proteins. In this review, we summarize the CE-based techniques coupled with absorption, LIF, and MS detection systems for the analysis of proteins mostly within the past 5 years. The basic principle of each technique and its advantages and disadvantages for protein analysis are discussed in brief. Advanced CE techniques, including on-column concentration techniques and high-efficiency multidimensional separation techniques, for high-throughput protein profiling of complex biological samples and/or of single cells are emphasized. Although the developed techniques provide improved peak capacity, they have not become practical tools for proteomics, mainly because of poor reproducibility, low-sample lading capacity, and low throughput due to ineffective interfaces between two separation dimensions and that between separation and MS systems. In order to identify the complexities and dynamics of the proteomes expressed by cells, tissues, or organisms, techniques providing improved analytical sensitivity, throughput, and dynamic ranges are still demanded.
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Affiliation(s)
- Yu-Fen Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
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Huang X, Ren J. On-line chemiluminescence detection for isoelectric focusing of heme proteins on microchips. Electrophoresis 2005; 26:3595-601. [PMID: 16136525 DOI: 10.1002/elps.200500076] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper we present a sensitive chemiluminescence (CL) detection of heme proteins coupled with microchip IEF. The detection principle was based on the catalytic effects of the heme proteins on the CL reaction of luminol-H2O2 enhanced by para-iodophenol. The glass microchip and poly(dimethylsiloxane) (PDMS)/glass microchip for IEF were fabricated using micromachining technology in the laboratory. The modes of CL detection were investigated and two microchips (glass, PDMS/glass) were compared. Certain proteins, such as cytochrome c, myoglobin, and horseradish peroxidase, were focused by use of Pharmalyte pH 3-10 as ampholytes. Hydroxypropylmethylcellulose was added to the sample solution in order to easily reduce protein interactions with the channel wall as well as the EOF. The focused proteins were transported by salt mobilization to the CL detection window. Cytochrome c, myoglobin, and horseradish peroxidase were well separated within 10 min on a glass chip and the detection limits (S/N=3) were 1.2x10(-7), 1.6x10(-7), and 1.0x10(-10) M, respectively.
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Affiliation(s)
- Xiangyi Huang
- College of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai, P.R. China
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Sakic B, Kirkham DL, Ballok DA, Mwanjewe J, Fearon IM, Macri J, Yu G, Sidor MM, Denburg JA, Szechtman H, Lau J, Ball AK, Doering LC. Proliferating brain cells are a target of neurotoxic CSF in systemic autoimmune disease. J Neuroimmunol 2005; 169:68-85. [PMID: 16198428 PMCID: PMC1634761 DOI: 10.1016/j.jneuroim.2005.08.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 08/01/2005] [Indexed: 12/31/2022]
Abstract
Brain atrophy, neurologic and psychiatric (NP) manifestations are common complications in the systemic autoimmune disease, lupus erythematosus (SLE). Here we show that the cerebrospinal fluid (CSF) from autoimmune MRL-lpr mice and a deceased NP-SLE patient reduce the viability of brain cells which proliferate in vitro. This detrimental effect was accompanied by periventricular neurodegeneration in the brains of autoimmune mice and profound in vivo neurotoxicity when their CSF was administered to the CNS of a rat. Multiple ionic responses with microfluorometry and protein peaks on electropherograms suggest more than one mechanism of cellular demise. Similar to the CSF from diseased MRL-lpr mice, the CSF from a deceased SLE patient with a history of psychosis, memory impairment, and seizures, reduced viability of the C17.2 neural stem cell line. Proposed mechanisms of cytotoxicity involve binding of intrathecally synthesized IgG autoantibodies to target(s) common to different mammalian species and neuronal populations. More importantly, these results indicate that the viability of proliferative neural cells can be compromised in systemic autoimmune disease. Antibody-mediated lesions of germinal layers may impair the regenerative capacity of the brain in NP-SLE and possibly, brain development and function in some forms of CNS disorders in which autoimmune phenomena have been documented.
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Affiliation(s)
- Boris Sakic
- Department of Psychiatry and Behavioural Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5
- * Corresponding author. Tel.: +1 905 525 9140x22617, 22850; fax: +1 905 522 8804. E-mail addresses: (B. Sakic), (D.L. Kirkham), (D.A. Ballok), (J. Mwanjewe), (I.M. Fearon), (J. Macri), (G. Yu), (M.M. Sidor), (J.A. Denburg), (H. Szechtman), (J. Lau), (A.K. Ball), (L.C. Doering)
| | - David L. Kirkham
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - David A. Ballok
- Department of Psychiatry and Behavioural Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5
| | - James Mwanjewe
- Department of Medicine, McMaster University, Hamilton, Canada
| | - Ian M. Fearon
- Department of Biology, McMaster University, Hamilton, Canada
| | - Joseph Macri
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Guanhua Yu
- Department of Psychiatry and Behavioural Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5
| | - Michelle M. Sidor
- Department of Psychiatry and Behavioural Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5
| | | | - Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, HSC Rm 4N81, McMaster University, 1200 Main St. West, Hamilton, Ontario, Canada L8N 3Z5
| | - Jonathan Lau
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Alexander K. Ball
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Laurie C. Doering
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
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Crowley TA, Hayes MA. Analysis of human blood serum using the off-line coupling of capillary isoelectric focusing to matrix-assisted laser desorption/ionization time of flight mass spectrometry. Proteomics 2005; 5:3798-804. [PMID: 16127730 DOI: 10.1002/pmic.200401212] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Off-line coupling of capillary IEF (CIEF) with matrix-assisted laser desorption/ionization mass spectrometry was utilized for the analysis of human blood serum. Serum proteins were initially separated by CIEF, and fractions of the isoelectric separation were eluted sequentially to a MALDI-TOF MS sample target. During pressure elution of the CIEF sample, voltage was maintained across the capillary system utilizing a sheath flow arrangement to minimize band broadening induced by the laminar flow field. Both pI and mass information were obtained from the complex biological sample, similar to traditional 2-DE techniques, and the platform was faster (hours versus days), more automatable, and simpler than 2-DE. The volume of raw sample present in the actual analysis was approximately 100 nL, making this technique well suited for very rare specimens. Additionally, the speed and simplicity of the technology make it an attractive technique for performing initial comparative analyses of complex samples.
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Affiliation(s)
- Timothy A Crowley
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA
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Casado B, Pannell LK, Whalen G, Clauw DJ, Baraniuk JN. Human neuroglobin protein in cerebrospinal fluid. Proteome Sci 2005; 3:2. [PMID: 15730566 PMCID: PMC554085 DOI: 10.1186/1477-5956-3-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Accepted: 02/25/2005] [Indexed: 11/29/2022] Open
Abstract
Background Neuroglobin is a hexacoordinated member of the globin family of proteins. It is predominantly localized to various brain regions and retina where it may play a role in protection against ischemia and nitric oxide-induced neural injury. Cerebrospinal fluid was collected from 12 chronic regional or systemic pain and 5 control subjects. Proteins were precipitated by addition of 50% 0.2 N acetic acid, 50% ethanol, 0.02% sodium bisulfite. The pellet was extensively digested with trypsin. Peptides were separated by capillary liquid chromatography using a gradient from 95% water to 95% acetonitrile in 0.2% formic acid, and eluted through a nanoelectrospray ionization interface into a quadrapole – time-of-flight dual mass spectrometer (QToF2, Waters, Milford, MA). Peptides were sequenced (PepSeq, MassLynx v3.5) and proteins identified using MASCOT ®. Results Six different neuroglobin peptides were identified in various combinations in 3 of 9 female pain subjects, but none in male pain, or female or male control subjects. Conclusion This is the first description of neuroglobin in cerebrospinal fluid. The mechanism(s) leading to its release in chronic pain states remain to be defined.
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Affiliation(s)
- Begona Casado
- Division of Rheumatology, Immunology & Allergy, Georgetown University, Washington DC 20007-2197, USA
- Dipartimento di Biochimica A. Castellani, Universita di Pavia, Pavia 27100, Italy
| | - Lewis K Pannell
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0508, USA
| | - Gail Whalen
- Division of Rheumatology, Immunology & Allergy, Georgetown University, Washington DC 20007-2197, USA
| | - Daniel J Clauw
- Department of Medicine, Division of Rheumatology, University of Michigan, Ann Arbor 48109, MI, USA
| | - James N Baraniuk
- Division of Rheumatology, Immunology & Allergy, Georgetown University, Washington DC 20007-2197, USA
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Powell PR, Ewing AG. Recent advances in the application of capillary electrophoresis to neuroscience. Anal Bioanal Chem 2005; 382:581-91. [PMID: 15726336 DOI: 10.1007/s00216-005-3075-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 12/29/2004] [Accepted: 01/17/2005] [Indexed: 05/01/2023]
Abstract
With fast separation times (seconds to minutes), minimal sample requirements (nanoliters to femtoliters), and excellent mass detection limits (femtomole to zeptomole), capillary electrophoresis (CE) is ideally suited for in vitro and in vivo sampling of neurological samples with a high degree of spatial resolution. Advances in extracellular fluid analysis employing improved microdialysis and push-pull perfusion sampling methodologies has enabled the resolution of neurotransmitters present in limited amounts using CE. Great progress has been made to resolve complex neuropeptides, amino acids, and biogenic amines in tissue and cell cultures. Finally, owing largely to the small volume sampling abilities of CE, investigations of single nerve cells, both invertebrate and mammalian, have been accomplished. These applications of CE to the advancement of neuroscience are presented.
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Affiliation(s)
- Paula R Powell
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA
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Affiliation(s)
- Wes W C Quigley
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
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Li W, Fries D, Alli A, Malik A. Positively Charged Sol−Gel Coatings for On-Line Preconcentration of Amino Acids in Capillary Electrophoresis. Anal Chem 2003; 76:218-27. [PMID: 14697054 DOI: 10.1021/ac0301696] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel on-line method is presented for the extraction and preconcentration of amino acids using a sol-gel-coated column coupled to a conventional UV/visible detector. The presented approach does not require any additional modification of the commercially available standard CE instrument. Extraction, stacking, and focusing techniques were used in the preconcentration procedures. Sol-gel coatings were created by using N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride (C18-TMS) in the coating sol solutions. Due to the presence of a positively charged quaternary ammonium moiety in C18-TMS, the resulting sol-gel coating carried a positive charge. For extraction, the pH of the samples was properly adjusted to impart a net negative charge to amino acids. A long plug of the sample was then passed through the sol-gel-coated capillary to facilitate extraction via electrostatic interaction between the positively charged sol-gel coating and the negatively charged amino acid molecules. Focusing of the extracted amino acids was accomplished through desorption of the extracted amino acid molecules carried out by local pH change. Two different methods are described. Both methods showed excellent extraction and preconcentration effects. Preconcentration results obtained on sol-gel-coated columns were compared with the CZE analysis performed on bare fused-silica columns with traditional sample injections. The described procedure provided a 150,000-fold enrichment effect for alanine. The two methods provided acceptable repeatability in terms of both peak height and migration time.
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Affiliation(s)
- Wen Li
- Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA
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