1
|
Leng C, Sun S, Lin W, Pavon JA, Gennaro L, Gunawan RC, Bu X, Yang T, Li S. Imaged capillary isoelectric focusing method development for charge variants of high DAR ADCs. Anal Chim Acta 2024; 1328:343176. [PMID: 39266202 DOI: 10.1016/j.aca.2024.343176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 07/12/2024] [Accepted: 08/27/2024] [Indexed: 09/14/2024]
Abstract
BACKGROUND Charge heterogeneity is a critical quality attribute for therapeutic biologics including antibody-drug conjugates (ADCs). Developing an ion exchange chromatography (IEX) or an imaged capillary isoelectric focusing (icIEF) method for ADCs with high drug-to-antibody ratio (DAR) is challenging because of the increased hydrophobicity from the payload-linker, DAR heterogeneity, and payload-linker instability. A sub-optimal method can be poorly stability-indicating due to the inability to discern contributions from charge and size variants conjugated with different number of drugs/payloads. Systematic strategy and guidance on charge variant method development is highly desired for high DAR ADCs with various complex structures. RESULTS This work encompasses the development and optimization of icIEF methods for high DAR ADCs of various DAR values (4-8) and payload linker chemistry. Method optimization focuses on improving resolution and stability indicating capabilities and differentiating contributions from the protein and payload-linker. Types, proportion, and combination of solubilizers and carrier ampholytes, as well as focusing parameters were interrogated. Our findings show that the structural units of the linker, the DAR, and the payload chemistry prescribe the selection of buffer, solubilizer, and ampholyte. We demonstrate that a stronger denaturant or solubilizer is needed for high DAR ADCs with polyethylene glycol (PEG)-containing linker structure compared to peptide linker. For unstable payload-linker, buffer system enhances sample stability which is vital to method robustness. In addition, a longer isoelectric focusing time is necessary for an ADC than its corresponding antibody to reach optimal focusing. SIGNIFICANCE To the best of our knowledge, this is the first comprehensive study on icIEF method development for charge variant determination of high DAR ADCs with unique physicochemical properties.
Collapse
Affiliation(s)
- Chuan Leng
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States.
| | - Shuwen Sun
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States
| | - Wei Lin
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States
| | | | - Lynn Gennaro
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States
| | - Rico C Gunawan
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States
| | - Xiaodong Bu
- Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ, 07065, United States
| | - Tong Yang
- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd, No. 666 Xinhua Avenue, Chengdu Cross-Strait Science and Technology Industry Development Park, Wenjiang District, Chengdu, Sichuan Province, PR China
| | - Senwu Li
- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd, No. 666 Xinhua Avenue, Chengdu Cross-Strait Science and Technology Industry Development Park, Wenjiang District, Chengdu, Sichuan Province, PR China
| |
Collapse
|
2
|
Krebs F, Scheller C, Grove-Heike K, Pohl L, Wätzig H. Isoelectric point determination by imaged CIEF of commercially available SARS-CoV-2 proteins and the hACE2 receptor. Electrophoresis 2021; 42:687-692. [PMID: 33533060 PMCID: PMC8013610 DOI: 10.1002/elps.202100015] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/18/2022]
Abstract
In order to contribute to the scientific research on the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), we have investigated the isoelectric points (pI) of several related proteins, which are commercially available: the receptor‐binding domain (RBD) with His‐ and Fc‐tag, the S1 subunit with His‐tag, the S1/S2 subunits with His‐tag and the human angiotensin‐converting enzyme 2 (hACE2) with His‐tag. First, the theoretical pI values, based on the amino acid (AA) sequences of the proteins, were calculated using the ProtParam tool from the Bioinformatics Resource Portal ExPASy. The proteins were then measured with the Maurice imaged CIEF system (native fluorescence detection), testing various measurement conditions, such as different ampholytes or ampholyte mixtures. Due to isoforms, we get sections with several peaks and not just one peak for each protein. The determined pI range for the RBD/Fc is 8.24–9.32 (theoretical pI: 8.55), for the RBD/His it is 7.36–9.88 (8.91) and for the S1/His it is 7.30–8.37 (7.80). The pI range of the S1/S2/His is 4.41–5.87 (no theoretical pI, AA sequence unknown) and for hACE2/His, the determined global range is 5.19–6.11 (5.60) for all experimental conditions chosen. All theoretically derived values were found within these ranges, usually close to the center. Therefore, we consider theoretical values as useful to make predictions about the isoelectric points of SARS‐CoV‐2 proteins. The experimental conditions had only a minor influence on the pI ranges obtained and mainly influenced the peak shapes.
Collapse
Affiliation(s)
- Finja Krebs
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Christin Scheller
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Kristina Grove-Heike
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Lena Pohl
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Hermann Wätzig
- Institute of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| |
Collapse
|
3
|
Corbett JR, Robinson DE, Patrie SM. Robustness and Ruggedness of Isoelectric Focusing and Superficially Porous Liquid Chromatography with Fourier Transform Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:346-354. [PMID: 33274937 PMCID: PMC10476448 DOI: 10.1021/jasms.0c00355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
An investigation of a multidimensional proteomics workflow composed of off-gel isoelectric focusing (IEF) and superficially porous liquid chromatography (SPLC) with Fourier transform mass spectrometry (FTMS) was completed in order to assess various figures of merit associated with intact protein measurements. Triplicate analysis performed at both high and low FTMS resolutions on the E. coli proteome resulted in ∼900 redundant proteoforms from 3 to 95 kDa. Normalization of the chromatographic axis to identified proteoforms enabled reproducible physicochemical property measurements between proteome replicates with inter-replicate variances of ±3 ppm mass error for proteoforms <30 kDa, ±1.1 Da for proteins >30 kDa, ±12 s retention time error, and ±0.21 pI units. The results for E. coli and standard proteins revealed a correlation between pI precision and proteoform abundance with species detected in multiple IEF fractions exhibiting pI precisions less than the theoretical resolution of the off-gel system (±0.05 vs ±0.17, respectively). Evaluation of differentially modified proteoforms of standard proteins revealed that high sample loads (100s μgrams) change the IEF pH gradient profile, leading to sample broadening that facilitates resolution of charged post-translational modifications (e.g., phosphorylation, sialylation). Despite the impact of sample load on IEF resolution, results on standard proteins measured directly or after being spiked into E. coli demonstrated that the reproducibility of the workflow permitted recombination of the MS signal across IEF fractions in a manner supporting the evaluation of three label-free quantitation metrics for intact protein studies (proteoforms, proteoform ratios, and protein) over 102-103 sample amount with low femtomole detection limits.
Collapse
Affiliation(s)
- John R Corbett
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
- Department of Bioengineering, UT Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Dana E Robinson
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| | - Steven M Patrie
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, United States
| |
Collapse
|
4
|
Chau MK, Arega NG, Nhung Tran NA, Song J, Lee S, Kim J, Chung M, Kim D. Capacitively coupled contactless conductivity detection for microfluidic capillary isoelectric focusing. Anal Chim Acta 2020; 1124:60-70. [PMID: 32534676 DOI: 10.1016/j.aca.2020.05.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/25/2020] [Accepted: 05/09/2020] [Indexed: 12/30/2022]
Abstract
We report capacitively coupled contactless conductivity detection (C4D) of proteins separated by microfluidic capillary isoelectric focusing (μCIEF). To elucidate the evolution of negative conductivity peaks during focusing and seek IEF conditions for sensitive conductivity detection, numerical simulation was performed using a model protein GFP (green fluorescence protein) and hypothetical carrier ampholytes (CAs). C4D was successfully applied to the μCIEF by optimizing assay conditions using a simple and effective pressure-mobilization approach. The conductivity and fluorescence signals of a focused GFP band were co-detected, confirming that the obtained negative C4D peak could be attributed to the actual protein, not the non-uniform background conductivity profile of the focused CAs. GFP concentrations of 10 nM-30 μM was quantified with a detection limit of 10 nM. Finally, the resolving power was analyzed by separating a mixture of R-phycoerythrin (pI 5.01), GFP-F64L (pI 5.48), and RK-GFP (pI 6.02). The conductivities of the three separated fluorescence proteins were measured with average separation resolution of 2.06. We expect the newly developed label-free μCIEF-C4D technique to be widely adopted as a portable, electronics-only protein-analysis tool.
Collapse
Affiliation(s)
- Minh Khang Chau
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Nebiyu Getachew Arega
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Nguyen Anh Nhung Tran
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Jin Song
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea
| | - Sangmin Lee
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Jintae Kim
- Department of Electrical Engineering, Konkuk University, Gwangjin-gu, Seoul, 05029, South Korea
| | - Minsub Chung
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul, 04066, South Korea
| | - Dohyun Kim
- Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea; Natural Science Research Institute, Myongji University, Yongin-si, Gyeonggi-do, 17508, South Korea.
| |
Collapse
|
5
|
Capillary isoelectric focusing with free or immobilized pH gradient in silica particles packed column. Anal Chim Acta 2019; 1079:230-236. [DOI: 10.1016/j.aca.2019.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/03/2019] [Accepted: 06/05/2019] [Indexed: 12/12/2022]
|
6
|
Kahle J, Wätzig H. Determination of protein charge variants with (imaged) capillary isoelectric focusing and capillary zone electrophoresis. Electrophoresis 2018; 39:2492-2511. [DOI: 10.1002/elps.201800079] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/03/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Julia Kahle
- Technische Universität Braunschweig; Institute of Medicinal and Pharmaceutical Chemistry; Braunschweig Germany
| | - Hermann Wätzig
- Technische Universität Braunschweig; Institute of Medicinal and Pharmaceutical Chemistry; Braunschweig Germany
| |
Collapse
|
7
|
Collinson MM, Higgins DA. Organosilane Chemical Gradients: Progress, Properties, and Promise. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:13719-13732. [PMID: 28849936 DOI: 10.1021/acs.langmuir.7b02259] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chemical gradients play an important role in nature, driving many different phenomena critical to life, including the transport of chemical species across membranes and the transport, attachment, and assembly of cells. Taking a cue from these natural processes, scientists and engineers are now working to develop synthetic chemical gradients for use in a broad range of applications, such as in high-throughput investigations of surface properties, as means to guide the motions and/or assembly of liquid droplets, vesicles, nanoparticles, and cells and as new media for stationary-phase-gradient chemical separations. Our groups have been working to develop new methods for preparing chemical gradients from organoalkoxysilane and organochlorosilane precursors and to obtain a better understanding of their properties on macroscopic to microscopic length scales. This review highlights our recent work on the development of controlled-rate infusion and infusion-withdrawal dip-coating methods for the preparation of gradients on planar glass and silicon substrates, on thin-layer chromatography plates, and in capillaries and monoliths for liquid chromatography. We also cover the new knowledge gained from the characterization of our gradients using sessile drop and Wilhelmy plate dynamic water contact angle measurements, X-ray photoelectron spectroscopy mapping, and single-molecule tracking and spectroscopy. Our studies reveal important evidence of phase separation and cooperative interactions occurring along multicomponent gradients. Emerging concepts and new directions in the preparation and characterization of organosilane-based chemical gradients are also discussed.
Collapse
Affiliation(s)
- Maryanne M Collinson
- Department of Chemistry, Virginia Commonwealth University , 1001 West Main Street, Richmond, Virginia 23284-2006, United States
| | - Daniel A Higgins
- Department of Chemistry, Kansas State University , 1212 Mid-Campus Drive North, Manhattan, Kansas 66506-0401, United States
| |
Collapse
|
8
|
The automatic use of capillary isoelectric focusing with whole column imaging detection for carbamazepine binding to human serum albumin. J Pharm Biomed Anal 2016; 127:9-17. [DOI: 10.1016/j.jpba.2016.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/01/2015] [Accepted: 01/10/2016] [Indexed: 12/23/2022]
|
9
|
Štěpánová S, Kašička V. Recent developments and applications of capillary and microchip electrophoresis in proteomic and peptidomic analyses. J Sep Sci 2015; 39:198-211. [DOI: 10.1002/jssc.201500973] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 10/06/2015] [Accepted: 10/06/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Sille Štěpánová
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague Czech Republic
| |
Collapse
|
10
|
Hühner J, Lämmerhofer M, Neusüß C. Capillary isoelectric focusing-mass spectrometry: Coupling strategies and applications. Electrophoresis 2015; 36:2670-2686. [DOI: 10.1002/elps.201500185] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/31/2015] [Accepted: 07/31/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Jens Hühner
- Faculty of Chemistry; Aalen University; Aalen Germany
| | - Michael Lämmerhofer
- Institute of Pharmaceutical Sciences; University of Tübingen; Tübingen Germany
| | | |
Collapse
|
11
|
Xia L, Lin F, Wu X, Liu C, Wang J, Tang Q, Yu S, Huang K, Deng Y, Geng L. On-chip protein isoelectric focusing using a photoimmobilized pH gradient†. J Sep Sci 2014; 37:3174-80. [DOI: 10.1002/jssc.201400795] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 07/23/2014] [Accepted: 08/02/2014] [Indexed: 02/01/2023]
Affiliation(s)
- Lin Xia
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - FengMing Lin
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Xin Wu
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Chuanli Liu
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Jianshe Wang
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Qi Tang
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Shiyong Yu
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Kunjie Huang
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Yulin Deng
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| | - Lina Geng
- School of Life Science; Beijing Institute of Technology; Beijing P. R. China
| |
Collapse
|
12
|
Creamer JS, Oborny NJ, Lunte SM. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2014; 6:5427-5449. [PMID: 25126117 PMCID: PMC4128283 DOI: 10.1039/c4ay00447g] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis.
Collapse
Affiliation(s)
- Jessica S. Creamer
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Nathan J. Oborny
- Department of Bioengineering, University of Kansas, Lawrence, KS, USA
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Susan M. Lunte
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Bioengineering, University of Kansas, Lawrence, KS, USA
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
| |
Collapse
|
13
|
Kannan B, Nokura K, Alvarez JC, Higgins DA, Collinson MM. Fabrication of surface charge gradients in open-tubular capillaries and their characterization by spatially resolved pulsed streaming potential measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15260-15265. [PMID: 24274139 DOI: 10.1021/la402934m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Surface charge gradients have been formed on the inside surface of 75 μm i.d. silica capillaries via controlled rate infusion using 3-aminopropyltriethoxysilane as the reactive precursor. These 400 mm length gradients have been characterized using spatially resolved streaming potential measurements, from which the zeta potential as a function of distance was determined. The gradient capillaries exhibited a gradual variation in zeta potential from top to bottom, whereas uniformly modified and as-received capillaries were relatively homogeneous along their length. For a gradient prepared with a relatively high concentration of aminosilane, the zeta potential changed over 60 mV from one end of the capillary to the other, yielding a variation in the magnitude of the apparent surface charge of ~7 fold. By changing the concentration of the aminoalkoxysilane and/or the rate of infusion, both the value of the zeta potential (and hence surface charge) and its spatial profile (i.e., rate of change with distance) could be manipulated.
Collapse
Affiliation(s)
- Balamurali Kannan
- Department of Chemistry, Virginia Commonwealth University , Richmond, Virginia 23284-2006, United States
| | | | | | | | | |
Collapse
|
14
|
Kašička V. Recent developments in capillary and microchip electroseparations of peptides (2011-2013). Electrophoresis 2013; 35:69-95. [PMID: 24255019 DOI: 10.1002/elps.201300331] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 01/15/2023]
Abstract
The review presents a comprehensive survey of recent developments and applications of capillary and microchip electroseparation methods (zone electrophoresis, ITP, IEF, affinity electrophoresis, EKC, and electrochromatography) for analysis, isolation, purification, and physicochemical and biochemical characterization of peptides. Advances in the investigation of electromigration properties of peptides, in the methodology of their analysis, including sample preseparation, preconcentration and derivatization, adsorption suppression and EOF control, as well as in detection of peptides, are presented. New developments in particular CE and CEC modes are reported and several types of their applications to peptide analysis are described: conventional qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. Some micropreparative peptide separations are shown and capabilities of CE and CEC techniques to provide relevant physicochemical characteristics of peptides are demonstrated.
Collapse
Affiliation(s)
- Václav Kašička
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| |
Collapse
|