1
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Estimation of pressure-, temperature- and frictional heating-related effects on proteins’ retention under ultra-high-pressure liquid chromatographic conditions. J Chromatogr A 2015; 1393:73-80. [DOI: 10.1016/j.chroma.2015.03.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/17/2015] [Accepted: 03/10/2015] [Indexed: 11/19/2022]
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2
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Ichibangase T, Nakata K, Imai K. Improved separation of fluorogenic derivatized intact proteins with high resolution and efficiency using a reversed-phase liquid chromatographic system. Biomed Chromatogr 2014; 28:862-7. [DOI: 10.1002/bmc.3172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tomoko Ichibangase
- Research Institute of Pharmaceutical Sciences; Musashino University; 1-1-20 Shinmachi, Nishitokyo-shi Tokyo Japan
| | - Katsunori Nakata
- Research Institute of Pharmaceutical Sciences; Musashino University; 1-1-20 Shinmachi, Nishitokyo-shi Tokyo Japan
| | - Kazuhiro Imai
- Research Institute of Pharmaceutical Sciences; Musashino University; 1-1-20 Shinmachi, Nishitokyo-shi Tokyo Japan
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3
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Hao DX, Huang YD, Wang K, Wei YP, Zhou WQ, Li J, Ma GH, Su ZG. Multiscale evaluation of pore curvature effects on protein structure in nanopores. J Mater Chem B 2014; 2:1770-1778. [DOI: 10.1039/c3tb21714k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper examined how pore curvature perturbed protein structures, by multiscale approaches including HPLC, confocal scanning, NMR H/D exchange, and molecular docking simulations.
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Affiliation(s)
- Dong-Xia Hao
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
| | - Yong-Dong Huang
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
| | - Kang Wang
- Chemical Engineering School
- Hebei University of Technology
- Tianjin, China
| | - Yu-Ping Wei
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
| | - Wei-Qing Zhou
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
| | - Juan Li
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
| | - Guang-Hui Ma
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
| | - Zhi-Guo Su
- National Key Lab of Biochemical Engineering
- Institute of Process Engineering
- Chinese Academy of Sciences
- Beijing, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
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4
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Fekete S, Veuthey JL, McCalley DV, Guillarme D. The effect of pressure and mobile phase velocity on the retention properties of small analytes and large biomolecules in ultra-high pressure liquid chromatography. J Chromatogr A 2012. [PMID: 23182282 DOI: 10.1016/j.chroma.2012.10.056] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A possible complication of ultra-high pressure liquid chromatography (UHPLC) is related to the effect of pressure and mobile phase velocity on the retention properties of the analytes. In the present work, numerous model compounds have been selected including small molecules, peptides, and proteins (such as monoclonal antibodies). Two instrumental setups were considered to attain elevated pressure drops, firstly the use of a post-column restrictor capillary at low mobile phase flow rate (pure effect of pressure) and secondly the increase of mobile phase flow rate without restrictor (i.e. a combined effect of pressure and frictional heating). In both conditions, the goal was to assess differences in retention behaviour, depending on the type or character of the analyte. An important conclusion is that the effect of pressure and mobile phase velocity on retention varied in proportion with the size of the molecule and in some cases showed very different behaviour. In isocratic mode, the pure effect of pressure (experiments with a post-column restrictor capillary) induces an increase in retention by 25-100% on small molecules (MW<300 g/mol), 150% for peptides (~1.3 kDa), 800% for insulin (~6 kDa) and up to >3000% for myoglobin (~17 kDa) for an increase in pressure from 100 bar up to 1100 bar. The important effect observed for the isocratic elution of proteins is probably related to conformational changes of the protein in addition to the effect of molecular size. Working in gradient elution mode, the pressure related effects on retention were found to be less pronounced but still present (an increase of apparent retention factor between 0.2 and 2.5 was observed).
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Affiliation(s)
- Szabolcs Fekete
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Bd d'Yvoy 20, 1211 Geneva 4, Switzerland.
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5
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Fekete S, Rudaz S, Fekete J, Guillarme D. Analysis of recombinant monoclonal antibodies by RPLC: Toward a generic method development approach. J Pharm Biomed Anal 2012; 70:158-68. [DOI: 10.1016/j.jpba.2012.06.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 05/29/2012] [Accepted: 06/15/2012] [Indexed: 01/06/2023]
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6
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Fekete S, Veuthey JL, Guillarme D. New trends in reversed-phase liquid chromatographic separations of therapeutic peptides and proteins: theory and applications. J Pharm Biomed Anal 2012; 69:9-27. [PMID: 22475515 DOI: 10.1016/j.jpba.2012.03.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 12/22/2022]
Abstract
In the pharmaceutical field, there is considerable interest in the use of peptides and proteins for therapeutic purposes. There are various ways to characterize such complex samples, but during the last few years, a significant number of technological developments have been brought to the field of RPLC and RPLC-MS. Thus, the present review focuses first on the basics of RPLC for peptides and proteins, including the inherent problems, some possible solutions and some directions for developing a new RPLC method that is dedicated to biomolecules. Then the latest advances in RPLC, such as wide-pore core-shell particles, fully porous sub-2 μm particles, organic monoliths, porous layer open tubular columns and elevated temperature, are described and critically discussed in terms of both kinetic efficiency and selectivity. Numerous applications with real samples are presented that confirm the relevance of these different strategies. Finally, one of the key advantages of RPLC for peptides and proteins over other historical approaches is its inherent compatibility with MS using both MALDI and ESI sources.
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Affiliation(s)
- Szabolcs Fekete
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Bd d'Yvoy 20, 1211 Geneva 4, Switzerland.
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7
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Wang Q, Lacher NA, Muralidhara BK, Schlittler MR, Aykent S, Demarest CW. Rapid and refined separation of human IgG2 disulfide isomers using superficially porous particles. J Sep Sci 2011; 33:2671-80. [PMID: 20730829 DOI: 10.1002/jssc.201000230] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A rapid reversed-phase HPLC separation of recombinant human immunoglobulin gamma 2 (IgG2) disulfide isomers using columns packed with superficially porous particles is reported. Under optimal conditions, a separation of monoclonal IgG2 disulfide isomers was achieved in 10 min using a Poroshell™ 300SB-C8 column via a combination of high column temperature (85°C), mobile phases with high eluotropic strength (e.g. isopropanol) and high flow rate (1.5 mL/min). Thermodynamic stability analyses of chromatographically enriched IgG2 disulfide isomers revealed differences in their individual denaturation temperatures, which correlate with the observed temperature-dependent refinement of peak profiles by reversed-phase HPLC. This reversed-phase HPLC method in conjunction with other orthogonal analytical techniques (e.g. capillary gel electrophoresis, peptide mapping, ion exchange chromatography, etc.) is being used to characterize disulfide isomers in the development of therapeutic IgG2 antibodies.
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Affiliation(s)
- Qian Wang
- Analytical R&D, Global Biologics, Pfizer Inc., Chesterfield, MO 63017, USA.
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8
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High temperature liquid chromatography of intact proteins using organic polymer monoliths and alternative solvent systems. J Chromatogr A 2010; 1217:3519-24. [DOI: 10.1016/j.chroma.2010.03.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 01/21/2010] [Accepted: 03/19/2010] [Indexed: 11/21/2022]
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9
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Nitric oxide stimulates myoglobin gene and protein expression in vascular smooth muscle. Biochem J 2009; 423:169-77. [PMID: 19650765 DOI: 10.1042/bj20090716] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Mb (myoglobin) is a haemoprotein present in cardiac, skeletal and smooth muscle and is primarily responsible for the storage and 'facilitated transfer' of molecular oxygen from the cell membrane to mitochondria. Also, Mb plays a role in regulating *NO (nitric oxide) homoeostasis through (i) binding *NO (Mb-NO complex); (ii) oxidation of *NO to nitrate; and (iii) formation of vasoactive S-nitroso-Mb [Rayner, B.S., Wu, B.-J., Raftery, M., Stocker, R. and Witting, P.K. (2005) J. Biol. Chem. 280, 9985-9993]. Pathological *NO concentrations affect mitochondrial function and decrease cell viability through inducing apoptosis. Treatment of cultured rat VSMCs (vascular smooth muscle cells) with cumulative doses (0.1, 1 or 10 microM) of *NO from the donors diethylamineNONOate or spermineNONOate (N-[2-aminoethyl]-N-[2-hydroxy-3-nitrosohydrazine]-1,2-ethelenediamine) yielded a time-dependent increase in Mb gene expression. Concomitant transcriptional activation increased the concentration of Mb within cultured rat or primary human VSMCs as judged by Western blot analysis and indirect immunofluorescence microscopy. Cell viability did not decrease in these cells at the *NO doses tested. Importantly, sub-culturing isolated rat aortic segments for 7 days in the presence of L-arginine at 37 degrees C stimulated *NO production with a parallel increase in Mb in the underlying VSMCs. Overall, exposure of VSMCs (either in cell culture or intact vessels) to pathological *NO promotes an up-regulation of the Mb gene and protein, suggesting a feedback relationship between *NO and Mb that regulates the concentration of the potent cell signalling molecule in the vessel wall, similar to the role haemoglobin plays in the vessel lumen.
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10
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Stanelle RD, Marcus RK. Nylon-6 capillary-channeled polymer (C-CP) fibers as a hydrophobic interaction chromatography stationary phase for the separation of proteins. Anal Bioanal Chem 2008; 393:273-81. [DOI: 10.1007/s00216-008-2457-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/26/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
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11
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Vailaya A. Fundamentals of Reversed Phase Chromatography: Thermodynamic and Exothermodynamic Treatment. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-200052969] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Anant Vailaya
- a Merck Research Laboratories , Rahway, New Jersey, USA
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12
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Nelson DM, Marcus RK. Characterization of Capillary-Channeled Polymer Fiber Stationary Phases for High-Performance Liquid Chromatography Protein Separations: Comparative Analysis with a Packed-Bed Column. Anal Chem 2006; 78:8462-71. [PMID: 17165840 DOI: 10.1021/ac061223w] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Capillary-channeled polymer (C-CP) fibers are investigated as reversed-phase (RP) stationary phases for high-performance liquid chromatography of proteins. A comparative analysis of column characteristics for polypropylene and poly(ethylene terephthalate) C-CP fiber columns and a conventional packed-bed (C4-derivatized silica) column has been undertaken. Five proteins (ribonuclease A, cytochrome c, lysozyme, myoglobin, bovine serum albumin) were used to investigate the separation characteristics under typical RP gradient conditions. Column performance was compared under standard (identical) and optimized RP chromatographic conditions. The gradient compositions utilized with the C-CP fiber columns are similar to those used with conventional columns, employing flow rates in the 1-6 mL/min range and gradient rates of approximately 1%/min. The packed-bed column was operated as prescribed by the column manufacturer. The retention factor (k'), separation factor (alpha), resolution (Rs), asymmetry factor (As), elution order, and peak capacity values of a four protein separations performed on the C-CP fiber columns are compared to the same separation on the C4 column. One unique feature observed here is the lessening of the percentage of organic modifier necessary to elute the proteins from the fiber phases with increased linear velocity. The potential contribution of the different stationary phases to protein denaturation was evaluated through a spectrophotometric enzymatic activity assay. The repeatability of retention times under both sets of conditions for six consecutive injections of lysozyme on each C-CP fiber column is < or =1.5% RSD. The column-to-column reproducibility of retention times for three columns of each fiber type is also < or =1.5% RSD. The overall performance of the C-CP fiber columns was comparable to the conventional column used in these studies. Basic characteristics demonstrated here suggested further developments in the areas of ultrafast protein separations and preparative-scale protein chromatography.
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Affiliation(s)
- Dwella M Nelson
- Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, South Carolina 29634, USA
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13
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Sawicka K, Sahota T, Taylor MJ, Tanna S. Development of a reversed-phase high-performance liquid chromatography method for the analysis of components from a closed-loop insulin delivery system. J Chromatogr A 2006; 1132:117-23. [PMID: 16901496 DOI: 10.1016/j.chroma.2006.07.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 07/11/2006] [Accepted: 07/25/2006] [Indexed: 11/30/2022]
Abstract
A reversed-phase HPLC method has been developed which enables separation of the three components of a closed-loop insulin delivery system, namely concanavalin A methacrylamide (Con A-MA), dextran methacrylate (Dex-MA) and bovine insulin. The analysis of Con A-MA represents a significant challenge due to the formation of multiple conformations on contact with the chromatographic surface and the mobile phase. The extent of conformational change is shown to be dependent on a number of parameters: column temperature, mobile phase pH, contact time with the chromatographic surface, salt type and concentration and the organic modifier. By manipulation of these variables, protein denaturation can be minimised and recovery improved.
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Affiliation(s)
- Kirsty Sawicka
- Leicester School of Pharmacy, Faculty of Health and Life Sciences, De Montfort University, The Gateway, Leicester LE1 9BH, UK
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14
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Dillon TM, Bondarenko PV, Rehder DS, Pipes GD, Kleemann GR, Ricci MS. Optimization of a reversed-phase high-performance liquid chromatography/mass spectrometry method for characterizing recombinant antibody heterogeneity and stability. J Chromatogr A 2006; 1120:112-20. [PMID: 16448656 DOI: 10.1016/j.chroma.2006.01.016] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 12/30/2005] [Accepted: 01/06/2006] [Indexed: 10/25/2022]
Abstract
An enhanced analytical RP-HPLC/MS method was developed for monitoring the stability and production of intact and fragmented monoclonal antibodies (MAbs). The use of high column temperatures (70-80 degrees C), organic solvents with high eluotropic strength coefficients (isopropyl and n-propyl alcohols), and Zorbax StableBond columns, were critical for good recovery and resolution of immunoglobulin G1 (IgG1) and IgG2 monoclonal antibodies. Using this method, cleavage products of a degraded IgG1 antibody were clearly separated and identified by in-line electrospray ionization time-of-flight (ESI-TOF) mass spectrometry generating exact masses and unique terminal ladder sequences. The glycosylation profile, including mapping of the terminal galactose and fucose heterogeneity of the N-linked sugars, was determined by mass spectrometry of intact MAbs. In addition, we discovered that several IgG2 MAbs exhibited greater structural heterogeneity compared to IgG1s. Mass spectral characterization data and reduction data suggested that the heterogeneity is disulfide related. This reversed-phase LC/MS method represents a key advancement in monitoring intact MAb production and stability.
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Affiliation(s)
- Thomas M Dillon
- Pharmaceutics Department, Amgen Inc., One Amgen Center Dr., Thousand Oaks, CA 91320, USA.
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15
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Szabelski P, Liu X, Guiochon G. Pressure-induced effects in the heterogeneous adsorption of insulin on chromatographic surfaces. J Chromatogr A 2003; 1015:43-52. [PMID: 14570318 DOI: 10.1016/s0021-9673(03)01286-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effect of increasing the average column pressure (ACP) on the heterogeneous adsorption of insulin variants on a C18-bonded silica was studied in isocratic reversed-phase HPLC. Adsorption isotherm data of lispro and porcine insulin obtained for values of the ACP ranging from 57 to 237 bar were fitted to the Langmuir-Freundlich and the Tóth equation. The resulting isotherm parameters, including the equilibrium adsorption constant and the heterogeneity index, were next used for the calculation of distribution functions characterizing the energy of interactions between the adsorbed insulin molecules and the stationary phase. It was observed that increasing the pressure by 180 bar causes a broadening of the distribution functions and a shift of the position of their maximum toward lower interaction energies. These findings suggest that, under high pressures, the insulin molecules interact with the stationary phase in a more diversified way than under low pressures. Additionally, the most probable value of the energy of the insulin-surface interactions becomes lower when the ACP increases. The pressure-induced changes in the interaction of insulin variants with the hydrophobic surface are attributed to a possible conformational flexibility of the molecular structure of this protein.
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Affiliation(s)
- Paweł Szabelski
- Department of Theoretical Chemistry, Maria Curie-Skłodowska University, pl. M.-C. Skłodowskiej 3, 20-031 Lublin, Poland
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16
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Tani H, Matsubara T, Kamidate T. Use of cholate derivatives with submicellar concentration for controlling selectivity of proteins in hydrophobic interaction chromatography. J Chromatogr A 2003; 1016:51-60. [PMID: 14601827 DOI: 10.1016/s0021-9673(03)01322-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Hydrophobic interaction chromatography (HIC) of proteins using a phenyl column has been performed in the presence of various surfactants with micellar and submicellar concentration ranges. Most surfactants were effective for a decrease in the retention of proteins in both concentration ranges. However, the use of anionic cholate derivatives increased the retention of the proteins with high isoelectric point, such as lysozyme, cytochrome c, and trypsin, in submicellar concentration range, and then decreased it above the critical micellar concentration, while the retention of the other proteins was monotonously decreased. The results of frontal chromatographic analysis of the surfactant and capillary electrophoresis for the proteins in the presence of surfactant show that in the submicellar concentration range, cholate derivatives allowed to be adsorbed on the stationary phase, while they exhibited no interactions with the proteins. Thus, it appeared that the increase in the retention of basic proteins was due to the electrostatic attraction between the proteins and cholate-modified stationary phase. We have applied the unique property of cholate to the separation of ovalbumin and lysozyme in egg white sample using hydrophobic chromatography.
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Affiliation(s)
- Hirofumi Tani
- Division of Molecular Chemistry, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Sapporo 060-8628, Japan.
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17
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Tibbs Jones T, Fernandez EJ. Alpha-lactalbumin tertiary structure changes on hydrophobic interaction chromatography surfaces. J Colloid Interface Sci 2003; 259:27-35. [PMID: 12651130 DOI: 10.1016/s0021-9797(02)00180-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogen exchange (HX) detected by mass spectrometry (MS) was used to analyze the structure of calcium-free alpha-lactalbumin, a model protein with marginal stability. Two chromatographic peaks were observed from samples of pure protein eluted from SOURCE phenyl hydrophobic interaction chromatography (HIC) media. Whole-protein HX measurements showed that the less-retained peak had solvent exposure similar to native protein in the absence of the HIC surface while the retained protein was nearly, although not fully, solvent exposed. The formation of these two peaks was kinetically limited. The protein also refolded successfully following elution. In addition, proteolytic fragmentation was used to analyze HX at the peptide level. This approach revealed that helix C was the most stable region of alpha-lactalbumin under native conditions and in the flow-through peak. Helix C also formed the core of residual native structure in the partially unfolded protein in the retained peak. The results suggest that residues that are most solvent accessible under native conditions may be those most likely to unfold upon adsorption.
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Affiliation(s)
- Tara Tibbs Jones
- Department of Chemical Engineering, University of Virginia, Charlottesville 22904-4741, USA
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18
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Walhagen K, Boysen RI, Hearn MTW, Unger KK. The CEC behaviour of several synthetic peptides related to the activin betaA-betaD subunits. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2003; 61:109-21. [PMID: 12558946 DOI: 10.1034/j.1399-3011.2003.00032.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The resolution of several structurally related synthetic peptides, derived from the loop 3 region of the activin betaA-betaD subunits, has been studied using capillary electrochromatography (CEC) with Hypersil n-octadecylsilica as the sorbent. The results confirm that the CEC migration of these peptides can be varied in a charge-state-specific manner as the properties of the background electrolyte, such as pH, salt concentration and content of organic modifier, or temperature are systematically changed. Acidic peptides followed similar trends in retention behaviour, which was distinctly different to that shown by more basic peptides. The CEC separation of these peptides with the Hypersil n-octadecyl-silica involved distinguishable contributions from both electrophoretic mobility and chromatographic retention. Temperature effects were reflected as variations in both the electro-osmotic flow and the electrophoretic mobility of the peptides. When the separation forces acting on the peptides were synergistic with the electro-osmotic flow, as, for example, with the positively charged peptides at a particular pH and buffer electrolyte composition, their retention coefficient, kappacec, decreased with increasing capillary temperature, whereas when the separation forces worked in opposite directions, as for example with negatively charged peptides, their kappacec values increased slightly with increasing temperature. Moreover, when the content of organic modifier, acetonitrile, was sufficiently high, e.g. > 40% (v/v) and nonpolar interactions with the Hypersil n-octadecyl-silica sorbent were suppressed, mixtures of both the basic and acidic synthetic peptides could be baseline resolved under isocratic conditions by exploiting the mutual processes of electrophoretic mobility and electrostatic interaction. A linear relationship between the ln kappacec values and the volume fractions, psi, of the organic modifier over a limited range of psi-values, was established for the negatively charged peptides under these isocratic conditions. These findings thus provide useful guidelines in a more general context for the resolution and analysis of structurally related synthetic peptides using CEC methods.
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19
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Antonucci V, Hicks MB, Lin Z, Reamer RA. Determination of minor conformational changes of a doxorubicin-peptide conjugate under chromatographic conditions. J Chromatogr A 2003; 983:73-82. [PMID: 12568371 DOI: 10.1016/s0021-9673(02)01653-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Thermodynamic analysis of the reversed-phase retention behavior of a doxorubicin-peptide conjugate demonstrated that the degree of non-linearity observed in Van't Hoff plots was impacted by mobile phase acetonitrile content over the 25-38% acetonitrile (v/v) range tested. Small decreases in the non-polar surface area of the doxorubicin-peptide conjugate as a function of temperature were estimated from these data using linear solvent strength relationships, suggesting that the retention behavior may be the result of minor analyte conformational changes during the chromatographic experiment. This hypothesis was supported via circular dichroism (CD), Raman and 1H NMR spectroscopic studies of the doxorubicin-peptide conjugate in selected chromatographic mobile phase compositions. The CD and Raman data indicated small changes to the apparent analyte microenvironment as a function of temperature and bulk solvent environment, while 1H NMR studies specifically demonstrated the environmental sensitivity of protons on three non-polar peptide residues and the proximal aromatic region of the analyte. Together, these data suggest that minor changes to the conformational order of the essentially random structure of the doxorubicin-peptide conjugate are sufficient to impact chromatographic performance.
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Affiliation(s)
- Vincent Antonucci
- Analytical Research, Merck Research Laboratories, Rahway, NJ 07065, USA.
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20
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Heam MTW, Quirino JP, Whisstock J, Terabe S. Thermal unfolding of proteins studied by coupled reversed-phase HPLC-electrospray ionization mass spectrometry techniques based on isotope exchange effects. Anal Chem 2002; 74:1467-75. [PMID: 11924594 DOI: 10.1021/ac0104173] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, a deuterium exchange procedure has been employed to evaluate the thermal stability of globular proteins under conditions that replicate their interactive behavior in reversed-phase high performance chromatographic (RP-HPLC) systems. In particular, this investigation has permitted the conformational stability of two proteins, hen egg white lysozyme (HEWL) and horse heart myoglobin (HMYO) to be examined under different temperature and low-pH solvent regimes. The results confirm that this experimental approach provides an efficient strategy to explore fundamental conformational features of polypeptides or proteins in their folded and partial unfolded states under these interactive conditions. In particular, this analytical procedure permits insight to be readily gained into the processes that occur when polypeptides and globular proteins interact with lipophilic liquid/ solid interfaces in the presence of water-organic solvent mixtures at different temperatures.
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Affiliation(s)
- Milton T W Heam
- Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
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21
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Lin FY, Chen WY, Hearn MTW. Thermodynamic analysis of the interaction between proteins and solid surfaces: application to liquid chromatography. J Mol Recognit 2002; 15:55-93. [PMID: 11954053 DOI: 10.1002/jmr.564] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Fu-Yung Lin
- Department of Chemical and Materials Engineering, National Central University Chung-Li, 320 Taiwan, Republic of China
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22
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Boysen RI, Jong AJO, Wilce JA, King GF, Hearn MTW. Role of interfacial hydrophobic residues in the stabilization of the leucine zipper structures of the transcription factors c-Fos and c-Jun. J Biol Chem 2002; 277:23-31. [PMID: 11602575 DOI: 10.1074/jbc.m104556200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study documents a new and versatile experimental approach to study the relative stabilization energetics of recombinant polypeptide and protein mutants. In particular, the effect of temperature change over the range of T = 278-338 K on the thermodynamics of interaction of several leucine zipper coiled-coil polypeptides related to the transcription factors, c-Fos and c-Jun, following binding to immobilized n-octyl ligands has been determined. Plots of the change in heat capacity, DeltaC(p)0, versus T, in combination with the corresponding van't Hoff plots, allow the energetics of the interaction of polypeptides with n-octyl ligands to be rationalized and the respective mid-point transition temperatures, T(m) values, determined for the melting of their supramolecular structures. The derived experimental data correlated well with information available from other procedures, confirming that this new approach provides complementary insight into the interaction thermodynamics and the molecular nature of the thermal stability of recombinant polypeptides in non-polar or other types of chemical environments.
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Affiliation(s)
- Reinhard I Boysen
- Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, P. O. Box 13D, Victoria 3800, Australia
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23
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Matyska MT, Pesek JJ, Boysen RI, Heam MT. Characterization of open tubular capillary electrochromatography columns for the analysis of synthetic peptides using isocratic conditions. Anal Chem 2001; 73:5116-25. [PMID: 11721908 DOI: 10.1021/ac010384r] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we report on investigations related to the performance characteristics of two different types of etched chemically (n-octadecyl- and cholesterol-) modified capillaries in the open tubular format of capillary electrochromatography (CEC) for the analysis of synthetic peptides. The results confirm that the nature of the surface chemistry used to modify the capillary wall and type of chemically bonded group employed can affect the selectivity as well as the resolution of peptide samples. The results are consistent with the participation of selective peptide interactions with the bonded phase, although other factors, such as the morphology of the capillary wall surfaces, appear to be also involved. Moreover, several surprising observations related to peptide-specific multi-zoning effects have been observed. Additional experimental variables that can also be utilized to affect the retention of peptides in this approach to OTCEC include the type and percentage of organic solvent modifier employed in the eluent and the pH of the buffer system. To evaluate the reproducibility of different batches of the n-octadecyl- and cholesterol-modified capillaries and the stability of the chemically modified surface, the OTCEC selectivity and peak shape behavior of two small basic molecules (serotonin and tryptamine) and two proteins (turkey and chicken lysozyme) were also investigated. Finally, the use of the "bubble" cell technology for creating the detector window has been shown to provide significantly higher detection sensitivity with peptides, as compared with the conventional capillary format.
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Affiliation(s)
- M T Matyska
- Department of Chemistry, San Jose State University, California 95192-0101, USA
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24
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Walhagen K, Unger KK, Hearn MT. Capillary electrochromatography analysis of hormonal cyclic and linear peptides. Anal Chem 2001; 73:4924-36. [PMID: 11681468 DOI: 10.1021/ac0013352] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The retention behavior of linear and cyclic peptides has been studied by capillary electrochromatography (CEC) with a variety of different n-alkyl silica reversed-phase sorbents and also with mixed-mode phases containing both strong cation-exchange (sulfonic acid) and n-alkyl groups bonded onto the silica surface, using eluents ranging from pH 2.0 to pH 5.0. Depending upon the amino acid sequence, electrochromatographic retention of the peptides was strongly affected by the composition of the eluent, its pH value, and the choice of sorbent packed into the capillaries. The dominant separation processes operating with these charged analytes could be modulated inter alia by the content of organic modifier, acetonitrile, in the eluent, with peptide resolution predominantly arising from electrophoretic migration processes at high acetonitrile content. As the concentration of acetonitrile was decreased, chromatographic retention processes became more pronounced. With the n-alkyl silica CEC columns used in this study, silanophilic interactions between the sorbents and the charged peptides could be suppressed by increasing the molarity of the buffer and by adjusting the pH of the eluent to lower values. On the other hand, electrostatic interactions between basic peptides and the surface of strong cation-exchanger, mixed-mode materials can be suppressed at low pH values by using higher ionic strength conditions in the eluent. Different selectivity behavior was achieved with desmopressin and the other peptides with Spherisorb C18/SCX and Hypersil mixed-mode materials when an identical eluent composition of 60% (v/v) acetonitrile with 7.6 mM triethylammonium phosphate, pH 3.0, was used. These findings confirm that the surface charge density of the sorbent fulfills an important role in the modulation of peptide selectivity in CEC. These studies also confirm that the dependency of the logarithm of the CEC retention coefficients, i.e., log Kcec, of a peptide separated with n-octadecyl silica sorbents under CEC conditions, on the volume fraction, psi, of the organic solvent modifier, acetonitrile, within the range of 0.20 < or = psi < or = 0.60, can be approximated by a linear relationship. Moreover, these studies show that the selectivity differences of peptides separated by CEC with nonpolar sorbents in packed capillary systems can be discussed in terms of semiempirical dependencies that link peptide retention behavior with their molecular descriptor properties, e.g., their hydrophobicity, surface charge anisotropy, surface area, molecular mass and intrinsic charge, and thus to their corresponding linear free energy relationships.
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Affiliation(s)
- K Walhagen
- Institut fur Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany
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25
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Hearn MT. Peptide analysis by rapid, orthogonal technologies with high separation selectivities and sensitivities. Biologicals 2001; 29:159-78. [PMID: 11851312 DOI: 10.1006/biol.2001.0309] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This article examines the current status of peptide analysis by orthogonal micro-/nano-separation strategies, with emphasis on the complementary use of high performance capillary liquid chromatography (micro-HPLC), capillary zonal electrophoresis (HPCZE), open tubular capillary electrochromatography (ot -CEC) and packed capillary electrochromatography (p -CEC). The ability to interface these techniques with mass spectroscopic (MS) procedures has enabled substantial progress to be made in the analysis of very small quantities of peptides, as well as proteins and other bio-macromolecules. As a consequence, the staged application of these high resolution techniques as part of the standardisation of biological products via robust, sensitive protocols is rapidly becoming a reality. Recent conceptual and theoretical advances have also allowed improved levels of prediction and optimisation of these procedures. Since significant differences in selectivity can be achieved with micro-HPLC, HPCZE and HPCEC respectively, collectively these sophisticated techniques provide unprecedented opportunities for the rapid, orthogonal and sensitive separation of complex mixtures of peptides and proteins. Several advantages of using these technologies in tandem are highlighted.
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Affiliation(s)
- M T Hearn
- Centre for Bioprocess Technology, Australian Centre for Research on Separation Science, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia.
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26
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Lin FY, Chen WY, Hearn MT. Microcalorimetric studies on the interaction mechanism between proteins and hydrophobic solid surfaces in hydrophobic interaction chromatography: effects of salts, hydrophobicity of the sorbent, and structure of the protein. Anal Chem 2001; 73:3875-83. [PMID: 11534710 DOI: 10.1021/ac0102056] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study examines the effects of different salts as well as the influence of the relative hydrophobicities of different sorbents on the adsorption processes of proteins in hydrophobic interaction chromatography (HIC). Comparative data acquired by the equilibrium binding analysis and by isothermal titration microcalorimetry (ITC) are presented. In particular, thermodynamic parameters, including the enthalpy changes, related to the interactions between several globular proteins and various Toyopearl 650 M sorbents under solvent conditions containing either 2.0 M ammonium sulfate or 2.0 M sodium sulfate at pH 7.0 and 298.15 K have been evaluated in terms of the molecular properties of these systems. The results reveal that the dependence of the free energy change, deltaGads, for protein adsorption to HIC sorbents on the salt composition can be mainly attributed to the enthalpy changes associated with protein and sorbent dehydration and hydrophobic interactions. Differences in binding mechanisms between the n-butyl- and phenyl-HIC sorbents were evident. In the latter case, the participation of pi-pi hydrophobic interactions leads to significant differences in the associated enthalpy and entropy changes. Furthermore, an increase in the hydrophobicity of either the sorbent or the protein resulted in more negative values for the free energy change, which arose mostly from dehydration processes. Entropic effects favoring HIC adsorption increased with an increase in the exposed nonpolar surface area of the protein. Consequently, an increased contribution from the entropy change to the respective change in free energy occurs when HIC sorbents or proteins of higher hydrophobicity are employed, with these larger entropy changes consistent with a change in the interaction mechanism from a binding event dominated by adsorption to a partitioning-like process. Data extracted from the ITC measurements also provided insight into the interaction mechanisms that occur between proteins and hydrophobic solid surfaces, yielding information that can be applied to the HIC purification of proteins according to the concept of critical hydrophobicity of the system and its thermodynamic consequences.
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Affiliation(s)
- F Y Lin
- Department of Chemical Engineering, National Central University, Chung-Li, Taiwan
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27
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Cserháti T, Forgács E, Deyl Z, Miksík I. Effect of molecular parameters on the binding of phenoxyacetic acid derivatives to albumins. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 753:87-92. [PMID: 11302451 DOI: 10.1016/s0378-4347(00)00422-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The interaction of 12 phenoxyacetic acid derivatives with human and serum albumin as well as with egg albumin was studied by charge-transfer reversed-phase (RP) thin-layer chromatography (TLC) and the relative strength of interaction was calculated. Each phenoxyacetic acid derivative interacted with human and bovine serum albumins whereas no interaction was observed with egg albumin. Stepwise regression analysis proved that the lipophilicity of the derivatives exert a significant impact on their capacity to bind to serum albumins. This result supports the hypothesis that the binding of phenoxyacetic acid derivatives to albumins may involve hydrophobic forces occurring between the corresponding apolar substructures of these derivatives and the amino acid side chains.
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Affiliation(s)
- T Cserháti
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
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28
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Abstract
This review focuses on the current state of peptide separation by capillary electroendoosmotic chromatography (CEC). When carried out under optimised conditions, peptide separation by CEC methods represents an orthogonal and complementary technique to micro-HPLC (micro-HPLC) and high-performance capillary zone electrophoresis (HPCZE). The origin of the selectivity differences that can be achieved with these three separation techniques (CEC, micro-HPLC and HPCZE), respectively are discussed, and the current limits of performance with CEC methods documented. Peptide separations by CEC methods with n-alkyl bonded silicas or mixed-mode phases are also illustrated. The development of different variants of CEC and pressurised CEC (also commonly referred to in the literature as electrically-assisted micro-HPLC) are examined. The potential of coupling CEC systems to mass spectrometers for real-time analyses of peptides or protein digests has been examined. Several future directions for the application of this technique in phenotype/proteomic and zeomic mapping of naturally occurring peptides and proteins are highlighted.
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Affiliation(s)
- K Walhagen
- Institut fur Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany
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29
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Doucette A, Craft D, Li L. Protein concentration and enzyme digestion on microbeads for MALDI-TOF peptides mass mapping of proteins from dilute solutions. Anal Chem 2000; 72:3355-62. [PMID: 10939411 DOI: 10.1021/ac000176j] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A method for generating peptide mass maps from dilute protein samples is presented. The method involves the concentration of proteins from aqueous solution by adsorption onto reversed-phase polymeric microbeads. These beads are then washed extensively to remove contaminants, after which the bound proteins are digested with trypsin. Analysis of the digestion products is performed by MALDI-TOF mass spectrometry following direct deposition of the beads on a MALDI target, along with the matrix solution. The procedure is demonstrated using solutions of cytochrome c, lysozyme, and bovine serum albumin. The results of these digests are compared to trypsin digestions of the protein samples without sample preconcentration. Comparative results are also presented for protein solutions contaminated with 2 M NaCl, 2 M urea, or sodium dodecyl sulfate at concentrations up to 0.02%. These results reveal that, with the microbead preconcentration procedure, peptide mass maps can routinely be generated from highly contaminated samples with a protein concentration of only 100 nM.
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Affiliation(s)
- A Doucette
- Department of Chemistry, University of Alberta, Edmonton, Canada
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