1
|
Abstract
In bottom-up proteomics, proteins are typically identified by enzymatic digestion into peptides, tandem mass spectrometry and comparison of the tandem mass spectra with those predicted from a sequence database for peptides within measurement uncertainty from the experimentally obtained mass. Although now decreasingly common, isolated proteins or simple protein mixtures can also be identified by measuring only the masses of the peptides resulting from the enzymatic digest, without any further fragmentation. Separation methods such as liquid chromatography and electrophoresis are often used to fractionate complex protein or peptide mixtures prior to analysis by mass spectrometry. Although the primary reason for this is to avoid ion suppression and improve data quality, these separations are based on physical and chemical properties of the peptides or proteins and therefore also provide information about them. Depending on the separation method, this could be protein molecular weight (SDS-PAGE), isoelectric point (IEF), charge at a known pH (ion exchange chromatography), or hydrophobicity (reversed phase chromatography). These separations produce approximate measurements on properties that to some extent can be predicted from amino acid sequences. In the case of molecular weight of proteins without posttranslational modifications this is straightforward: simply add the molecular weights of the amino acid residues in the protein. For IEF, charge and hydrophobicity, the order of the amino acids, and folding state of the peptide or protein also matter, but it is nevertheless possible to predict the behavior of peptides and proteins in these separation methods to a degree which renders such predictions useful. This chapter reviews the topic of using data from separation methods for identification and validation in proteomics, with special emphasis on predicting retention times of tryptic peptides in reversed-phase chromatography under acidic conditions, as this is one of the most commonly used separation methods in bottom-up proteomics.
Collapse
|
2
|
Falconer IB, Mant CT, McKnight CJ, Vugmeyster L, Hodges R. Optimized purification of a fusion protein by reversed-phase high performance liquid chromatography informed by the linear solvent strength model. J Chromatogr A 2017; 1521:44-52. [PMID: 28942999 DOI: 10.1016/j.chroma.2017.08.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/07/2017] [Accepted: 08/24/2017] [Indexed: 11/19/2022]
Abstract
Fusion protein systems are commonly used for expression of small proteins and peptides. An important criterion for a fusion protein system to be useful is the ability to separate the protein of interest from the tag. Additionally, because no protease cleaves fusion proteins with 100% efficiency, the ability to separate the desired peptide from any remaining uncleaved protein is also necessary. This is likely to be the more difficult task as at least a portion of the sequence of the fusion protein is identical to that of the protein of interest. When a high level of purity is required, gradient elution reversed-phase HPLC is frequently used as a final purification step. Shallow gradients are often advantageous for maximizing both the purity and yield of the final product; however, the relationship between relative retention times at shallow gradients and those at steeper gradients typically used for analytical HPLC are not always straightforward. In this work, we report reversed-phase HPLC results for the fusion protein system consisting of the N-terminal domain of ribosomal protein L9 (NTL9) and the 36-residue villin headpiece subdomain (HP36) linked by a recognition sequence for the protease factor Xa. This system represents an excellent example of the difficulties in purification that may arise from this unexpected elution behavior at shallow gradients. Additionally, we report on the sensitivity of this elution behavior to the concentration of the additive trifluoroacetic acid in the mobile phase and present optimized conditions for separating HP36 from the full fusion protein by reversed-phase HPLC using a shallow gradient. Finally, we suggest that these findings are relevant to the purification of other fusion protein systems, for which similar problems may arise, and support this suggestion using insights from the linear solvent strength model of gradient elution liquid chromatography.
Collapse
Affiliation(s)
- Isaac B Falconer
- Deparment of Chemistry, University of Colorado Denver, Denver, CO, 80204, United States
| | - Colin T Mant
- Department of Biochemistry and Molecular Genetics, University of Colorado, School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - C James McKnight
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States
| | - Liliya Vugmeyster
- Deparment of Chemistry, University of Colorado Denver, Denver, CO, 80204, United States.
| | - Robert Hodges
- Department of Biochemistry and Molecular Genetics, University of Colorado, School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, United States.
| |
Collapse
|
3
|
Gorshkov AV, Pridatchenko ML, Perlova TY, Tarasova IA, Levitsky LI, Gorshkov MV, Evreinov VV. Applicability of the critical chromatography concept to proteomic problems. II. Effect of mobile phase on the separation of peptides and proteins taking into account the amino acid sequence. JOURNAL OF ANALYTICAL CHEMISTRY 2017. [DOI: 10.1134/s106193481610004x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
4
|
Tarasova IA, Goloborodko AA, Perlova TY, Pridatchenko ML, Gorshkov AV, Evreinov VV, Ivanov AR, Gorshkov MV. Application of Statistical Thermodynamics To Predict the Adsorption Properties of Polypeptides in Reversed-Phase HPLC. Anal Chem 2015; 87:6562-9. [DOI: 10.1021/acs.analchem.5b00595] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Irina A. Tarasova
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Anton A. Goloborodko
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Tatyana Y. Perlova
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Marina L. Pridatchenko
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Alexander V. Gorshkov
- N.
N. Semenov’s Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Victor V. Evreinov
- N.
N. Semenov’s Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexander R. Ivanov
- Barnett
Institute of Chemical and Biological Analysis, Department of Chemistry
and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Mikhail V. Gorshkov
- Institute
for Energy Problems of Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology (State University), 141707 Dolgoprudny, Moscow Region, Russia
| |
Collapse
|
5
|
Abstract
In bottom-up proteomics, proteins are typically identified by enzymatic digestion into peptides, tandem mass spectrometry and comparison of the tandem mass spectra with those predicted from a sequence database for peptides within measurement uncertainty from the experimentally obtained mass. Although now decreasingly common, isolated proteins or simple protein mixtures can also be identified by measuring only the masses of the peptides resulting from the enzymatic digest, without any further fragmentation. Separation methods such as liquid chromatography and electrophoresis are often used to fractionate complex protein or peptide mixtures prior to analysis by mass spectrometry. Although the primary reason for this is to avoid ion suppression and improve data quality, these separations are based on physical and chemical properties of the peptides or proteins and therefore also provide information about them. Depending on the separation method, this could be protein molecular weight (SDS-PAGE), isoelectric point (IEF), charge at a known pH (ion exchange chromatography), or hydrophobicity (reversed phase chromatography). These separations produce approximate measurements on properties that to some extent can be predicted from amino acid sequences. In the case of molecular weight of proteins without posttranslational modifications this is straightforward: simply add the molecular weights of the amino acid residues in the protein. For IEF, charge and hydrophobicity, the order of the amino acids, and folding state of the peptide or protein also matter, but it is nevertheless possible to predict the behavior of peptides and proteins in these separation methods to a degree which renders such predictions useful. This chapter reviews the topic of using data from separation methods for identification and validation in proteomics, with special emphasis on predicting retention times of tryptic peptides in reversed-phase chromatography under acidic conditions, as this is one of the most commonly used separation methods in proteomics.
Collapse
Affiliation(s)
- Alex A Henneman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | | |
Collapse
|
6
|
A model for predicting slopes S in the basic equation for the linear-solvent-strength theory of peptide separation by reversed-phase high-performance liquid chromatography. J Chromatogr A 2010; 1217:489-97. [DOI: 10.1016/j.chroma.2009.11.065] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 10/21/2009] [Accepted: 11/23/2009] [Indexed: 11/20/2022]
|
7
|
Krokhin OV, Spicer V. Peptide Retention Standards and Hydrophobicity Indexes in Reversed-Phase High-Performance Liquid Chromatography of Peptides. Anal Chem 2009; 81:9522-30. [DOI: 10.1021/ac9016693] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oleg V. Krokhin
- Department of Internal Medicine, University of Manitoba, Manitoba Centre for Proteomics and Systems Biology, 799 JBRC, 715 McDermot Avenue, Winnipeg, MB, R3E 3P4, Canada, and Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Vic Spicer
- Department of Internal Medicine, University of Manitoba, Manitoba Centre for Proteomics and Systems Biology, 799 JBRC, 715 McDermot Avenue, Winnipeg, MB, R3E 3P4, Canada, and Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| |
Collapse
|
8
|
Klammer AA, Yi X, MacCoss MJ, Noble WS. Improving Tandem Mass Spectrum Identification Using Peptide Retention Time Prediction across Diverse Chromatography Conditions. Anal Chem 2007; 79:6111-8. [PMID: 17622186 DOI: 10.1021/ac070262k] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most algorithms for identifying peptides from tandem mass spectra use information only from the final spectrum, ignoring non-mass-based information acquired routinely in liquid chromatography tandem mass spectrometry analyses. One physiochemical property that is always obtained but rarely exploited is peptide chromatographic retention time. Efforts to use chromatographic retention time to improve peptide identification are complicated because of the variability of retention time in different experimental conditions-making retention time calculations nongeneralizable. We show that peptide retention time can be reliably predicted by training and testing a support vector regressor on a small collection of data from a single liquid chromatography run. This model can be used to filter peptide identifications with observed retention time that deviates from predicted retention time. After filtering, positive peptide identifications increase by as much as 50% at a false discovery rate of 3%. We demonstrate that our dynamically trained model generalizes well across diverse chromatography conditions and methods for generating peptides, in particular improving peptide identification using nonspecific proteases.
Collapse
Affiliation(s)
- Aaron A Klammer
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | | | | | | |
Collapse
|
9
|
Liu H, Finch JW, Lavallee MJ, Collamati RA, Benevides CC, Gebler JC. Effects of column length, particle size, gradient length and flow rate on peak capacity of nano-scale liquid chromatography for peptide separations. J Chromatogr A 2007; 1147:30-6. [PMID: 17320886 DOI: 10.1016/j.chroma.2007.02.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 01/26/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
The effects of the column length, the particle size, the gradient length and the flow rate of a nanoLC system on peptide peak capacity were investigated and compared. Columns packed with 1.7 microm and 3 microm C(18) materials into pieces of 75 microm capillary tubing of various lengths were tested with different gradient lengths and flow rates. While increasing the length of a column packed with the 1.7 microm material helped improve peptide peak capacity at the whole range of the tested gradient lengths (24-432 min), little improvement in peak capacity was observed with the increase of the length of a column packed with the 3 microm material unless a gradient longer than 50 min was carried out. Up to 30% of peak capacity increase was observed when a column's length is doubled, with little reduction in the throughput. In most cases, more than 50% of the increase in peak capacity was obtained with the reduction in the particle size from 3 microm to 1.7 microm. With the same backpressure generated, a shorter 1.7-microm-particle column outperformed a longer column packed with the 3 microm material. In a flow rate range of 100-700 nl/min, increasing the flow rate improved peak capacity for columns packed with 1.7 microm and 3 microm materials.
Collapse
Affiliation(s)
- Hongji Liu
- Life Science R&D, Waters Corporation, 34 Maple Street, Milford, MA 01757, USA.
| | | | | | | | | | | |
Collapse
|
10
|
Colinge J, Masselot A, Carbonell P, Appel RD. InSilicoSpectro: An Open-Source Proteomics Library. J Proteome Res 2006; 5:619-24. [PMID: 16512677 DOI: 10.1021/pr0504236] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a new proteomics open-source project, InSilicoSpectro, aimed at implementing recurrent computations that are necessary for proteomics data analysis. Illustrative examples are mass list file format conversions, protein sequence digestion, theoretical peptide and fragment mass computations, graphical display, matching with experimental data, isoelectric point estimation, and peptide retention time prediction. The project library is written in Perl, a widely used scripting language in bioinformatics, and it offers a unique framework of integrated objects to implement complex proteomics data analyses. For instance, only a few lines of code are required to digest a protein with fixed and variable modifications, label peptides with 18O, compute the fragmentation spectra and display their match with experimental spectra. We believe that InSilicoSpectro will be of great help to bioinformaticians, without detailed knowledge of proteomics specifics, and to mass spectrometrists with computer programming interest as well.
Collapse
Affiliation(s)
- Jacques Colinge
- Upper Austria University of Applied Sciences at Hagenberg, Bioinformatics Department, Hauptstrasse 117, A-4232 Hagenberg, Austria.
| | | | | | | |
Collapse
|
11
|
|
12
|
Palmblad M, Ramström M, Markides KE, Håkansson P, Bergquist J. Prediction of chromatographic retention and protein identification in liquid chromatography/mass spectrometry. Anal Chem 2002; 74:5826-30. [PMID: 12463368 DOI: 10.1021/ac0256890] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Liquid chromatography coupled on- or off-line with mass spectrometry is rapidly advancing as a tool in proteomics capable of dealing with the inherent complexity in biology and complementing conventional approaches based on two-dimensional gel electrophoresis. Proteins can be identified by proteolytic digestion and peptide mass fingerprinting or by searching databases using short-sequence tags generated by tandem mass spectrometry. This paper shows that information on the chromatographic behavior of peptides can assist protein identification by peptide mass fingerprinting in liquid chromatography/mass spectrometry. This additional information is significant and already available at no extra experimental cost.
Collapse
Affiliation(s)
- Magnus Palmblad
- The Angstrom Laboratory, Division of Ion Physics, Box 534, and Institute of Chemistry, Department of Analytical Chemistry, Box 531, Uppsala University, SE-751 21 Uppsala, Sweden.
| | | | | | | | | |
Collapse
|
13
|
van der Ven C, Gruppen H, de Bont DB, Voragen AG. Reversed phase and size exclusion chromatography of milk protein hydrolysates: relation between elution from reversed phase column and apparent molecular weight distribution. Int Dairy J 2001. [DOI: 10.1016/s0958-6946(01)00032-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
14
|
Agatonović-Kustrin S, Zecević M, Zivanović L, Tucker IG. Structure-retention relationships of diuretics in reversed-phase liquid chromatography. Biomed Chromatogr 2000; 14:41-3. [PMID: 10664562 DOI: 10.1002/(sici)1099-0801(200002)14:1<41::aid-bmc964>3.0.co;2-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
15
|
Agatonovic-Kustrin S, Zecevic M, Zivanovic L. Use of ANN modelling in structure--retention relationships of diuretics in RP-HPLC. J Pharm Biomed Anal 1999; 21:95-103. [PMID: 10701917 DOI: 10.1016/s0731-7085(99)00133-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Structure retention relationship study, conducted by RP HPLC, was used to investigate physical chemical parameters related to the RP retention times of amiloride, hydrochlorothiazide and methyldopa in order to predict the separation of amiloride and methylclothiazide from Lometazid tablets. Retention data were obtained with an ODS column using a mobile phase methanol water (pH adjusted with phosphoric acid). Physical chemical properties were calculated directly from the molecular structure. Artificial neural networks (ANNs) were used to correlate chromatograms retention times with mobile phase composition and pH, and with physical chemical properties of amiloride, hydrochlorothiazide and methyldopa and to predict separation of amiloride and methylclothiazide from Lometazid tablets. Sensitivity analysis was performed to interpret the meaning of the descriptors included in the models. Results confirmed the dominant role of the polar modifier in such chromatographic systems. Within a series of solutes chromatographed under identical conditions, the retention parameters could be approximated by a non-linear combination of logP, logD, pKa, surface tension, parachor, molar volume and to minor extend by polarisability, reetractivity index and density. This study has demonstrated that the use ANNs techniques can result in much more efficient use of experimental information. As HPLC is the most popular analytical technique, improvements in HPLC methods development can yield significant gains in the overall analytical effort. The ANNs extension presented could be the method of choice in some advanced research settings and serves as an indication of the broad potential of neural networks in chromatography analysis.
Collapse
|
16
|
Sereda TJ, Mant CT, Hodges RS. Selectivity due to conformational differences between helical and non-helical peptides in reversed-phase chromatography. J Chromatogr A 1995; 695:205-21. [PMID: 7757204 DOI: 10.1016/0021-9673(94)01147-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The reversed-phase retention behaviour of two series of peptides, one non-helical and the other alpha-helical, was studied under various linear AB gradients in order to determine the effect of peptide conformation on selectivity of the separation. The non-helical series, designated X1, with the sequence Ac-XLGAKGAGVG-amide, exhibited negligible alpha-helical content in a hydrophobic medium; whereas, the amphipathic alpha-helical series, designated AX9, with the sequence Ac-EAEKAAKEXEKAAKEAEK-amide, exhibited high alpha-helical content in a hydrophobic medium. We have shown that plots of log k vs. phi (where k is the median capacity factor and phi is the median volume fraction of organic solvent) are very similar for any one peptide conformation, i.e., peptides from either the non-helical or amphipathic alpha-helical series exhibit similar S (solute parameter) values and the b (gradient steepness parameter) values are also similar for 17 different amino acid substitutions within each series of peptides. If mixtures of peptides from the two different series are separated using either increasing or decreasing gradient rates, large increases in resolution occur due to selectivity, which may be attributed to the difference in the log k vs. phi plots for each series of peptides. In addition, by using a polymer of an X1 peptide, which is 20 residues in length, it has been shown that the molecular mass difference between the X1 and the AX9 series of peptides is not sufficient to account for the selectivity difference. The S value of a non-amphipathic alpha-helical peptide further suggested that the difference in selectivity between the two series of peptides was due to differences in conformation. We believe that the peptide mixtures presented here provide a good model for studying selectivity effects due to conformational differences between peptides, an important concern when attempting to develop rational approaches to the prediction and optimization of peptide separation protocols from primary sequence information alone.
Collapse
Affiliation(s)
- T J Sereda
- Department of Biochemistry, University of Alberta, Edmonton, Canada
| | | | | |
Collapse
|
17
|
Lang E, Szendrei GI, Lee VM, Otvos L. Spectroscopic evidence that monoclonal antibodies recognize the dominant conformation of medium-sized synthetic peptides. J Immunol Methods 1994; 170:103-15. [PMID: 7512605 DOI: 10.1016/0022-1759(94)90250-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Spectroscopic methods have amply documented that small- and medium-sized peptides tend to assume unordered conformations in water. The conformational tendencies, however, manifest in halogenated alcohols, and the preferred secondary structures are apparent from the circular dichroism (CD) spectra. Here we report the results of immobilizing peptide and protein antigens from various mixtures of trifluoroethanol and water during enzyme-linked immunosorbent assays. The increased recognition by the appropriate monoclonal antibodies (mAbs) is correlated with the increase of the alpha helical, beta turn, or beta pleated sheet content of the peptides presented in the different solvent mixtures. Remarkably, the antibody binding can be detected at considerably lower antigen levels if the antigen is immobilized from trifluoroethanol. The antigens we used corresponded to fragments of normal human neurofilaments and tau protein found in the paired helical filaments of Alzheimer's disease, and the nucleoprotein of rabies virus. The conformation of myoglobin is as stable in water as in trifluoroethanol, and therefore acted as a negative control. Indeed, the recognition of myoglobin did not increase upon increasing the trifluoroethanol concentration in the solvent used to apply the antigen to the plate. The possibility of imperfect binding to the plastic carrier or nonspecific binding to irrelevant antibodies is excluded by using control experiments. We offer the first direct evidence that the mAbs recognize the secondary structure of epitopes, and that it is possible to correlate the binding conformation of the epitopes with CD measurements made in trifluoroethanol-water mixtures.
Collapse
Affiliation(s)
- E Lang
- Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104
| | | | | | | |
Collapse
|
18
|
Mahieu JP, Gosselet NM, Sebille B, Garel MC, Beuzard Y. Reactivity of 42 disulfides with thiol group of human haemoglobin and human serum albumin. Int J Biol Macromol 1993; 15:233-40. [PMID: 8373743 DOI: 10.1016/0141-8130(93)90043-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The reactivities of disulfides of different compound families towards thiol groups of human haemoglobin and human serum albumin were determined at physiological pH 7.4 by anion-exchange liquid chromatography. The apparent second-order kinetic rate constants, K1, were calculated for the reaction of these disulfides with each protein. The results show that the studied heterocyclic disulfides are the most reactive compounds with both proteins. The lipophilic properties of these disulfides were evaluated by reversed-phase high performance liquid chromatography, using the percentage of acetonitrile (PAC) required for eluting each compound of the chromatographic column in a water-acetonitrile gradient. The structure-reactivity correlations between log K1 and log PAC are stated for each protein and compared. They fit a parabolic curve which permits one to define a lipophilic domain corresponding to a quantitative reaction of disulfides towards these proteins. The studied disulfides present a similar optimum of reactivity for both proteins.
Collapse
Affiliation(s)
- J P Mahieu
- Laboratoire de Physico-Chimie des Biopolymères, Unité Mixte CNRS No. 27, Thiais, France
| | | | | | | | | |
Collapse
|
19
|
Application of non-porous silica ultramicrospheres to high-performance liquid chromatographic column packings. J Chromatogr A 1992. [DOI: 10.1016/0021-9673(92)80148-n] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
20
|
Otvos L, Urge L, Thurin J. Influence of different N- and O-linked carbohydrates on the retention times of synthetic peptides in reversed-phase high-performance liquid chromatography. J Chromatogr A 1992; 599:43-9. [PMID: 1618992 DOI: 10.1016/0021-9673(92)85457-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Glycopeptides consisting of 6-19 amino acid residues and different mono- and disaccharides attached to single asparagine and serine residues were synthesized on solid-phase and were characterized by reversed-phase high-performance liquid chromatography and circular dichroism. It was shown that the decreased retention times due to glycosylation could be correlated with the increasing length of the sugar moiety. Phosphorylation of the same sequences reduced the retention times 1.6 times more than glycosylation with monosaccharides did. The binding to the column was dependent on the structure of the disaccharide when derivatized and glycosylated asparagine, the building block of N-glycopeptide syntheses was studied. However, this structural dependence of the elution times disappeared in the final glycopeptides. Although both glycosylation and phosphorylation resulted in altered secondary structure of the peptide backbone, it appears that the retention times reflect the increased hydrophilicity more strongly than induced conformational orientation on the surface of the bonded phase.
Collapse
Affiliation(s)
- L Otvos
- Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104
| | | | | |
Collapse
|