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Gao T, Li X, Jia Z, Hendrickx F, Falmagne JB, Chen HX. Rapid Capillary Zone Electrophoresis of Recombinant Erythropoietin by the Use of Dynamic Double Layer Coating. ANAL LETT 2020. [DOI: 10.1080/00032719.2020.1750023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - Xiang Li
- National Institute of Food and Drug Control, Beijing, China
| | - Zeng Jia
- Beijing BioCEart Technology Institute, Beijing, China
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2
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Glatz Z. On-capillary derivatisation as an approach to enhancing sensitivity in capillary electrophoresis. Electrophoresis 2014; 36:744-63. [DOI: 10.1002/elps.201400449] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 10/09/2014] [Accepted: 10/11/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Zdeněk Glatz
- Department of Biochemistry; Faculty of Science and CEITEC; Masaryk University; Brno Czech Republic
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3
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Pang N, Bai Y, Zhou Y, Yang X, Zhang Z, Nie H, Fu X, Liu H. Rapid and subnanomolar assay of recombinant human erythropoietin by capillary electrophoresis using NanoOrange precolumn labeling and laser-induced fluorescence detection. J Sep Sci 2014; 37:2233-8. [DOI: 10.1002/jssc.201400263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/07/2014] [Accepted: 05/12/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Nannan Pang
- School of Chemical and Biological Engineering; University of Science and Technology; Beijing P. R. China
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Yu Bai
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Yu Zhou
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Xia Yang
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Zhengxiang Zhang
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Honggang Nie
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Xiaofang Fu
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
| | - Huwei Liu
- Beijing National Laboratory for Molecular Sciences, the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry; College of Chemistry and Molecular Engineering, Peking University; Beijing P. R. China
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4
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Zhao SS, Chen DDY. Applications of capillary electrophoresis in characterizing recombinant protein therapeutics. Electrophoresis 2013; 35:96-108. [PMID: 24123141 DOI: 10.1002/elps.201300372] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/16/2013] [Accepted: 09/18/2013] [Indexed: 12/15/2022]
Abstract
The use of recombinant protein for therapeutic applications has increased significantly in the last three decades. The heterogeneity of these proteins, often caused by the complex biosynthesis pathways and the subsequent PTMs, poses a challenge for drug characterization to ensure its safety, quality, integrity, and efficacy. CE, with its simple instrumentation, superior separation efficiency, small sample consumption, and short analysis time, is a well-suited analytical tool for therapeutic protein characterization. Different separation modes, including CIEF, SDS-CGE, CZE, and CE-MS, provide complementary information of the proteins. The CE applications for recombinant therapeutic proteins from the year 2000 to June 2013 are reviewed and technical concerns are discussed in this article.
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Affiliation(s)
- Shuai Sherry Zhao
- Department of Chemistry, University of British Columbia, Vancouver, Canada
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5
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de Kort BJ, de Jong GJ, Somsen GW. Profiling of erythropoietin products by capillary electrophoresis with native fluorescence detection. Electrophoresis 2012; 33:2996-3001. [DOI: 10.1002/elps.201200303] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/05/2012] [Accepted: 08/02/2012] [Indexed: 12/22/2022]
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6
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Wang H, Dou P, Lü C, Liu Z. Immuno-magnetic beads-based extraction-capillary zone electrophoresis-deep UV laser-induced fluorescence analysis of erythropoietin. J Chromatogr A 2012; 1246:48-54. [DOI: 10.1016/j.chroma.2012.02.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 02/03/2012] [Accepted: 02/06/2012] [Indexed: 01/08/2023]
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7
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Taichrib A, Pioch M, Neusüß C. Toward a screening method for the analysis of small intact proteins by CE-ESI-TOF MS. Electrophoresis 2012; 33:1356-66. [DOI: 10.1002/elps.201100620] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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8
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Girard M, Puerta A, Diez-Masa JC, de Frutos M. High resolution separation methods for the determination of intact human erythropoiesis stimulating agents. A review. Anal Chim Acta 2012; 713:7-22. [DOI: 10.1016/j.aca.2011.11.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 11/10/2011] [Accepted: 11/11/2011] [Indexed: 12/17/2022]
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9
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Protein glycosylation analysis with capillary-based electromigrative separation techniques. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s12566-010-0018-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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10
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Optimization and qualification of capillary zone electrophoresis method for glycoprotein isoform distribution of erythropoietin for quality control laboratory. J Pharm Biomed Anal 2009; 50:538-43. [DOI: 10.1016/j.jpba.2009.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 05/08/2009] [Accepted: 05/08/2009] [Indexed: 11/21/2022]
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11
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Dou P, Liu Z, He J, Xu JJ, Chen HY. Rapid and high-resolution glycoform profiling of recombinant human erythropoietin by capillary isoelectric focusing with whole column imaging detection. J Chromatogr A 2008; 1190:372-6. [DOI: 10.1016/j.chroma.2008.03.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 02/24/2008] [Accepted: 03/03/2008] [Indexed: 01/01/2023]
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12
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Giménez E, Benavente F, Barbosa J, Sanz-Nebot V. Analysis of intact erythropoietin and novel erythropoiesis-stimulating protein by capillary electrophoresis-electrospray-ion trap mass spectrometry. Electrophoresis 2008; 29:2161-70. [DOI: 10.1002/elps.200700788] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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12 CE in impurity profiling of drugs. CAPILLARY ELECTROPHORESIS METHODS FOR PHARMACEUTICAL ANALYSIS 2008. [DOI: 10.1016/s0149-6395(07)00012-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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Lara-Quintanar P, Lacunza I, Sanz J, Diez-Masa JC, de Frutos M. Immunochromatographic removal of albumin in erythropoietin biopharmaceutical formulations for its analysis by capillary electrophoresis. J Chromatogr A 2007; 1153:227-34. [PMID: 16919660 DOI: 10.1016/j.chroma.2006.07.079] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 11/17/2022]
Abstract
Human serum albumin (HSA) is added to some pharmaceutical preparations as an excipient. This is the case for some of the commercial preparations of recombinant erythropoietin (rEPO). Differences in the number of the sialic acid moieties in the different rEPO glycoforms confer to these forms different net charges and different bioactivity. Knowledge of the isoforms present in each pharmaceutical product is then of interest. Differences in net charge of the rEPO forms make possible their separation by electrophoretical methods. However it has been observed in our laboratory that the amount of HSA usually present in these drug formulations interferes or even precludes separation of rEPO bands by capillary zone electrophoresis (CZE). In this work, an immunochromatographic method to remove HSA from rEPO biopharmaceutical formulations and a procedure to concentrate the sample that is needed to be performed prior to the analysis by CZE are developed. A home-made computer program to compare the percentage of correct assignments of electrophoretical bands provided by different migration parameters is used to study the effect of HSA remaining in samples on the accuracy of assignment of rEPO bands. When there exists a residual concentration of HSA in the sample (<2mg/ml) only the effective electrophoretic mobility is a reliable migration parameter to assign rEPO bands with a 100% of correct assignment. This parameter allows the correct assignment of bands of rEPO from pharmaceutical products formulated with HSA after immunochromatographic removal of HSA. Electrophoretical bands found in epoetin alpha, one of the commercial formulations of rEPO, are independent of the molecular mass of the excipients. The methodology used in this work for the analysis by CZE and the assignment of rEPO isoforms, as well as for the immunochromatographic HSA removal in the pharmaceutical products could be of high interest for the health authorities to control the quality of the product in marketing surveillance studies and for the quality control laboratories of the manufacturers.
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Affiliation(s)
- Pilar Lara-Quintanar
- Institute of Organic Chemistry (C.S.I.C.), Juan de la Cierva 3, 28006 Madrid, Spain
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15
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Abstract
CE- and microchip-based separations coupled with LIF are powerful tools for the separation, detection and determination of biomolecules. CE with certain configurations has the potential to detect a small number of molecules or even a single molecule, thanks to the high spatial coherence of the laser source which permits the excitation of very small sample volumes with high efficiency. This review article discusses the use of LIF detection for the analysis of peptides and proteins in CE. The most common laser sources, basic instrumentation, derivatization modes and set-ups are briefly presented and special attention is paid to the different fluorogenic agents used for pre-, on- and postcapillary derivatization of the functional groups of these compounds. A table summarizing major applications of these derivatization reactions to the analysis of peptides and proteins in CE-LIF and a bibliography with 184 references are provided which covers papers published to the end of 2005.
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16
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Benavente F, Giménez E, Olivieri AC, Barbosa J, Sanz-Nebot V. Estimation of the composition of recombinant human erythropoietin mixtures using capillary electrophoresis and multivariate calibration methods. Electrophoresis 2006; 27:4008-15. [PMID: 17054091 DOI: 10.1002/elps.200600132] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A multivariate calibration method using partial least-squares (PLS) is proposed in order to characterize binary mixtures of two types of recombinant human erythropoietin (epoetin alpha and beta), based on the analysis of the highly overlapped UV-electrophoretic profiles obtained with the CE methodology recommended by the European Pharmacopoeia (EurPh). A two-factor PLS-1 model was developed and validated using mixtures of alpha and beta epoetins. Glycoforms were identified according to their effective electrophoretic mobility values and the normalized area values of each glycoform peak were used as multivariate data. Calibration and validation results were satisfactory. The PLS-1 model was successfully used for determination of epoetin alpha and beta contents in the rHuEPO provided by the EurPh as a biological reference product.
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Affiliation(s)
- Fernando Benavente
- Departamento de Química Analítica, Universidad de Barcelona, Barcelona, Spain.
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17
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Kamoda S, Kakehi K. Capillary electrophoresis for the analysis of glycoprotein pharmaceuticals. Electrophoresis 2006; 27:2495-504. [PMID: 16718643 DOI: 10.1002/elps.200500853] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Carbohydrate chains in glycoprotein pharmaceuticals play important roles for the expression of their biological activities, but the structure and compositions of carbohydrate chains are dependent on the conditions for their production. Therefore, evaluation of the carbohydrate chains is quite important for productive process development, characterization of product for approval application, and routine quality control. The oligosaccharides themselves have complex structure including blanching and various glycosidic linkages, and oligosaccharides in one glycoprotein pharmaceutical generally have high heterogeneity, and characterization of oligosaccharide moiety in glycoprotein has been a challenging target. In these situations, CE has been realized as a powerful tool for oligosaccharide analysis due to its high resolution and automatic operating system. This review focuses on the application of CE to the glycoform analysis of glycoproteins and profiling of the N-linked glycans released from glycoprotein pharmaceuticals. Current applications for structure analysis using CE-MS(n) technique and glycan profiling method for therapeutic antibody are also described.
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Affiliation(s)
- Satoru Kamoda
- Faculty of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
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18
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Erny GL, Elvira C, San Román J, Cifuentes A. Capillary electrophoresis using copolymers of different composition as physical coatings: A comparative study. Electrophoresis 2006; 27:1041-9. [PMID: 16470781 DOI: 10.1002/elps.200500692] [Citation(s) in RCA: 39] [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 work, a comparative study on the use of different polymers as physically adsorbed coatings for CE is presented. It is demonstrated that the use of ad hoc synthesized polymers as coatings allows tailoring the EOF in CE increasing the flexibility of this analytical technique. Namely, different polymers were synthesized at our laboratory using different percentages of ethylpyrrolidine methacrylate (EpyM) and N,N-dimethylacrylamide (DMA). Thus, by modifying the percentage of EpyM and DMA monomers it is possible to manipulate the positive charge of the copolymer, varying the global electrical charge on the capillary wall and with that the EOF. These coated capillaries are obtained by simply flushing a given EpyM-DMA aqueous solution into bare silica capillaries. It is shown that by using these coated capillaries at adequate pHs, faster or more resolved CE separations can be achieved depending on the requirements of each analysis. Moreover, it is demonstrated that these coated capillaries reduce the electrostatic adsorption of basic proteins onto the capillary wall. Furthermore, EpyM-DMA coatings allow the reproducible chiral separation of enantiomers through the partial filling technique (PFT). The EpyM-DMA coated capillaries are demonstrated to provide reproducible EOF values independently of the pH and polymer composition with%RSD values lower than 2% for the same day. It is also demonstrated that the coating procedure is reproducible between capillaries. The compatibility of this coating protocol with CE in microchips is discussed.
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19
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Madajová V, Simunicová E, Kaniansky D, Marák J, Zelenská V. Fractionation of glycoforms of recombinant human erythropoietin by preparative capillary isotachophoresis. Electrophoresis 2005; 26:2664-73. [PMID: 15929059 DOI: 10.1002/elps.200500044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This feasibility study deals with the use of preparative capillary isotachophoresis (CITP), operating in a discontinuous fractionation mode, to the separations and isolations of glycoforms of recombinant human erythropoietin (rhEPO). The preparative CITP separations were monitored by capillary zone electrophoresis (CZE) with a hydrodynamically closed separation unit. Such a CZE system, suppressing fluctuations of the migration data linked with fluctuations of EOF and hydrodynamic flow, made possible to evaluate and compare the preparative CITP separations performed within a longer time frame. Preparative CITP, carried out in the separation unit with coupled columns of enhanced sample loadability, separating 100 microg of rhEPO in a run lasting ca. 30 min, gave the production rate higher than 55 ng/s for the rhEPO glycoforms. The preparative separations included valve isolations of the glycoforms from the ITP stack into four or six fractions. Such numbers of the fractions corresponded to typical numbers of the major glycoform peaks as resolved in CZE of rhEPO. With respect to close effective mobilities of the glycoforms and a multicomponent nature of rhEPO, the fractions contained mixtures of glycoforms with the dominant glycoforms enriched 10-100-fold, relative to the original rhEPO sample.
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Affiliation(s)
- Vlasta Madajová
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
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20
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Neusüss C, Demelbauer U, Pelzing M. Glycoform characterization of intact erythropoietin by capillary electrophoresis-electrospray-time of flight-mass spectrometry. Electrophoresis 2005; 26:1442-50. [PMID: 15759301 DOI: 10.1002/elps.200410269] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Glycosylated proteins often show a large variation in their glycosylation pattern, complicating their structural characterization. In this paper, we present a method for the accurate mass determination of intact isomeric glycoproteins based on capillary electrophoresis-electrospray-time of flight-mass spectrometry. Human recombinant erythropoietin has been chosen as a showcase. The approach enables the on-line removal of nonglycosylated proteins, salts, and neutral and negatively charged species. More important, different glycosylation forms are separated both on the base of differences in the number of negatively charged sialic acid residues and the size of the glycans. Thus, 44 glycoforms and in total about 135 isoforms of recombinant human erythropoietin, taking also acetylation into account, could be distinguished for the reference material from the European Pharmacopeia. Distinct glycosylation differences for samples from different suppliers are clearly observed. Based on the accurate mass an overall composition of each single isoform is proposed, perfectly in agreement with data on glycan and glycopeptide analysis. This method is an ideal complement to the established techniques for glycopeptide and glycan analysis, not differentiating branching or linkage isoforms, but leading to an overall composition of the glycoprotein. The presented strategy is expected to improve significantly the ability to characterize and quantify isomeric glycoforms for a large variety of glycoproteins.
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21
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Sanz-Nebot V, Benavente F, Giménez E, Barbosa J. Capillary electrophoresis and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry for analysis of the novel erythropoiesis-stimulating protein (NESP). Electrophoresis 2005; 26:1451-6. [PMID: 15759304 DOI: 10.1002/elps.200410092] [Citation(s) in RCA: 31] [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
NESP (novel erythropoiesis-stimulating protein) is a recently approved hyperglycosylated analogue of human erythropoietin (EPO) with a long-lasting effect. In this work, the capillary electrophoresis (CE) methodology proposed by the European Pharmacopoeia for the separation of EPO glycoforms has been modified for the separation of NESP glycoforms. Optimization of pH of the separation electrolyte has been fundamental in order to achieve baseline resolution of seven peaks corresponding to NESP glycoforms. Intact NESP has also been characterized by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). An accurate approximation to an average molecular mass of the NESP molecule has been obtained, taking into account the strong influence of laser intensity upon the MALDI-TOF mass spectra found.
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Affiliation(s)
- Victoria Sanz-Nebot
- Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.
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22
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Stübiger G, Marchetti M, Nagano M, Reichel C, Gmeiner G, Allmaier G. Characterisation of intact recombinant human erythropoietins applied in doping by means of planar gel electrophoretic techniques and matrix-assisted laser desorption/ionisation linear time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:728-742. [PMID: 15700237 DOI: 10.1002/rcm.1830] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Our experiments show that it is possible to detect different types of recombinant human erythropoietins (rhEPOs), EPO-alpha, EPO-beta and novel erythropoesis stimulating protein (NESP), based on exact molecular weight (MW) determination by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) applying a high-resolution time-of-flight (TOF) mass analyser in the linear mode. Detection limits for the highly purified, intact glycoproteins were achievable in the low fmol range (25-50 fmol) using a sample preparation method applying a hydrophobic sample support (DropStop) as MALDI target surface. These results are very promising for the development of highly sensitive detection methods for a direct identification of rhEPO after enrichment from human body fluids. During our investigation we were able to differentiate EPO-alpha, EPO-beta and NESP based on distinct molecular substructures at the protein level by specific enzymatic reactions. MW determination of the intact molecules by high resolving one-dimensional sodium dodecyl sulfate /polyacrylamide gel electrophoresis (1D SDS-PAGE) and isoform separation by planar isoelectric focusing (IEF) was compared with MALDI-MS data. Migration differences between the rhEPOs were observed from gel electrophoresis, whereby MWs of 38 kDa in the case of EPO-alpha/beta and 49 kDa for NESP could be estimated. In contrast, an exact MW determination by MALDI-MS based on internal calibration revealed average MWs of 29.8 +/- 0.3 kDa for EPO-alpha/beta and 36.8 +/- 0.4 kDa for NESP. IEF separation of the intact rhEPOs revealed the presence of four to eight distinct isoforms in EPO-alpha and EPO-beta, while four isoforms, which appeared in the more acidic area of the gels, were detected by immunostaining in NESP. A direct detection of the different N- or O-glycoform pattern from rhEPOs using MALDI-MS was possible by de-sialylation of the glycan structures and after de-N-glycosylation of the intact molecules. Thereby, the main glycoforms of EPO-alpha, EPO-beta and NESP could be characterised based on their N-glycan composition. A microheterogeneity of the molecules based on the degree of sialylation of the O-glycan was observable directly from the de-N-glycosylated protein.
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Affiliation(s)
- Gerald Stübiger
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, A-1060 Vienna, Austria
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23
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Simó C, Elvira C, González N, San Román J, Barbas C, Cifuentes A. Capillary electrophoresis-mass spectrometry of basic proteins using a new physically adsorbed polymer coating. Some applications in food analysis. Electrophoresis 2004; 25:2056-2064. [PMID: 15237406 DOI: 10.1002/elps.200305790] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A new physically adsorbed capillary coating for capillary electrophoresis-mass spectrometry (CE-MS) of basic proteins is presented, which is easily obtained by flushing the capillary with a polymer aqueous solution for two min. This coating significantly reduces the electrostatic adsorption of a group of basic proteins (i.e., cytochrome c, lysozyme, and ribonuclease A) onto the capillary wall allowing their analysis by CE-MS. The coating protocol is compatible with electrospray inonization (ESI)-MS via the reproducible separation of the standard basic proteins (%RSD values (n = 5) < 1% for analysis time reproducibility and < 5% for peak heights, measured from the total ion electropherograms (TIEs) within the same day). The LODs determined using cytochrome c with total ion current and extracted ion current defection were 24.5 and 2.9 fmol, respectively. Using this new coating lysozymes from chicken and turkey egg white could be easily distinguished by CE-MS, demonstrating the usefulness of this method to differentiate animal species. Even after sterilization at 120 degrees C for 30 min, lysozyme could be detected, as well as in wines at concentrations much lower than the limit marked by the EC Commission Regulation. Adulteration of minced meat with 5% of egg-white could also be analysed by our CE-MS protocol.
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Affiliation(s)
| | - Carlos Elvira
- Institute of Science and Technology of Polymers (CSIC)
| | | | - J San Román
- Institute of Science and Technology of Polymers (CSIC)
| | - Coral Barbas
- Department of Analytical Chemistry, University San Pablo-CEU, Madrid, Spain
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24
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Sanz-Nebot V, Benavente F, Vallverdú A, Guzman NA, Barbosa J. Separation of Recombinant Human Erythropoietin Glycoforms by Capillary Electrophoresis Using Volatile Electrolytes. Assessment of Mass Spectrometry for the Characterization of Erythropoietin Glycoforms. Anal Chem 2003; 75:5220-9. [PMID: 14708798 DOI: 10.1021/ac030171x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The separation of the glycoforms of erythropoietin (EPO) by capillary electrophoresis (CE) was recently published as a monograph by the European Pharmacopoeia (European Pharmacopoeia 4 2002, 1316, 1123-1128). Although the experimental CE conditions employed a background electrolyte containing additives suitable for on-line UV-absorption detection, they were not appropriate for on-line mass spectrometry (MS) detection. In this work, an attempt was made to investigate experimental conditions employing volatile electrolyte systems to achieve the separation and characterization of EPO glycoforms using CE and ESI-MS methodologies. The influence of several operating conditions, such as the coating of the internal walls of the capillary as well as the composition, concentration, and the pH of the separation buffer were investigated. The results demonstrated that when the internal walls of the capillaries were permanently coated with Polybrene and a buffer electrolyte containing 400 mM of HAc-NH4Ac (acetic acid-ammonium acetate), pH 4.75, was used, a significantly reproducible separation was achieved for EPO glycoforms. Intact EPO was characterized by two mass spectrometry techniques: electrospray ionization (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF-MS). The data demonstrated that MALDI-TOF-MS provided a good approximation to an average molecular mass of the EPO molecule. However, it was still necessary to carry out further separation of the intact EPO glycoforms in order to obtain molecular mass information when ESI-MS was used.
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Affiliation(s)
- Victoria Sanz-Nebot
- Department of Analytical Chemistry, University of Barcelona, 08028 Barcelona, Spain.
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González N, Elvira C, San Román J, Cifuentes A. New physically adsorbed polymer coating for reproducible separations of basic and acidic proteins by capillary electrophoresis. J Chromatogr A 2003; 1012:95-101. [PMID: 14509346 DOI: 10.1016/s0021-9673(03)01175-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this work, a new physically adsorbed coating for capillary electrophoresis (CE) is presented. The coating is based on a N,N-dimethylacrylamide-ethylpyrrolidine methacrylate (DMA-EPyM) copolymer synthesized in our laboratory. The capillary coating is simple and easy to obtain as only requires flushing the capillary with a polymer aqueous solution for 2 min. It is shown that by using these coated capillaries the electrostatic adsorption of a group of basic proteins onto the capillary wall is significantly reduced allowing their analysis by CE. Moreover, the DMA-EPyM coating provides reproducible separations of the basic proteins with RSD values for migration times lower than 0.75% for the same day (n = 5) and lower than 3.90% for three different days (n = 15). Interestingly, the electrical charge of the coated capillary wall can be modulated by varying the pH of the running buffer which makes possible the analysis of basic and acidic proteins in the same capillary. The usefulness of this coating is further demonstrated via the reproducible separation of whey (i.e. acidic) proteins from raw milk. The coating protocol should be compatible with both CE in microchips and CE-MS of different types of proteins.
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Affiliation(s)
- Nieves González
- Institute of Science and Technology of Polymers (CSIC) Juan de la Cierva 3, 28006 Madrid, Spain
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