651
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Zhou P, Liu X, Labuza TP. Moisture-induced aggregation of whey proteins in a protein/buffer model system. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:2048-2054. [PMID: 18311919 DOI: 10.1021/jf073151v] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Moisture-induced protein aggregation in a dry or intermediate-moisture food matrix can contribute to the loss of product acceptability. The present study evaluated the molecular mechanisms and controlling factors for moisture-induced whey protein aggregation in a premixed protein/buffer model system. Insoluble aggregates rapidly formed during the first 3 days of storage at 35 degrees C with a slower rate afterward. Evaluation of the insoluble aggregates by solubility tests in solutions containing SDS/urea/guanidine HCl/dithiothreitol and gel electrophoresis showed that the formation of intermolecular disulfide bonds was the main mechanism for protein aggregation, and all major whey proteins were involved in the formation of insoluble aggregates. Effects of various factors on aggregation were also investigated, including moisture content, medium pH, and the addition of NaCl. The dependence of aggregation on moisture content was bell-shaped, and the maximal extent of aggregation was achieved at a moisture content of around 70-80% on a dry weight basis.
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Affiliation(s)
- Peng Zhou
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, People's Republic of China
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652
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Kreye F, Siepmann F, Siepmann J. Lipid implants as drug delivery systems. Expert Opin Drug Deliv 2008; 5:291-307. [DOI: 10.1517/17425247.5.3.291] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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653
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Mahler HC, Printz M, Kopf R, Schuller R, Müller R. Behaviour of Polysorbate 20 During Dialysis, Concentration and Filtration Using Membrane Separation Techniques. J Pharm Sci 2008; 97:764-74. [PMID: 17688279 DOI: 10.1002/jps.21029] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
During formulation development of a therapeutic protein, combinations of buffers, pH and excipients need to be tested. As the protein bulk solution used for formulation development usually contains a buffer component at a defined pH and potentially one or more excipients already, this bulk requires to be processed. In case low concentrations of non-ionic surfactants, for example polysorbate 20, are already present in the bulk, the surfactant needs to be removed in lab-scale for further development use. The scope of the work was to study the behaviour of low concentrations of polysorbate 20 during membrane separation processes. The first part focuses on evaluating the behaviour of polysorbate 20 during a dialysis process, whereas the second part analyses concentration changes of polysorbate during a membrane concentration process using a stirred cell. The third part analyses potential membrane absorption of polysorbate at sterilizing-grade filters. In conclusion, it was found that polysorbate could not be significantly reduced during a dialysis process and accumulated during a membrane concentration process in unreproducable manner. During sterile filtration, no significant influence on the concentration of polysorbate was measurable. In any case, it is recommendable to quantify the concentration of polysorbate during critical membrane process steps in pharmaceutical industry.
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Affiliation(s)
- Hanns-Christian Mahler
- F. Hoffmann-La Roche Ltd., Formulation R&D Biologics, Pharmaceutical and Analytical R&D, Basel, Switzerland.
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654
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Lu Y, Harding SE, Rowe AJ, Davis KG, Fish B, Varley P, Gee C, Mulot S. The Effect of a Point Mutation on the Stability of IgG4 as Monitored by Analytical Ultracentrifugation. J Pharm Sci 2008; 97:960-9. [PMID: 17722105 DOI: 10.1002/jps.21016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
There is presently considerable interest in the state of aggregation and biophysical integrity of antibody preparations, and recent advances in the analysis of data from the analytical ultracentrifuge renders it a powerful probe of these stability phenomena, under both storage and freeze-thaw conditions. Solutions of a wild-type IgG4 antibody and a single amino acid hinge mutant IgG4m (serine residue 241 converted to proline) were exposed to different accelerated stress conditions, namely (i) elevated temperature storage for various periods (up to 59 days at 37 degrees C) or (ii) a series of freeze-thaw cycles (storage at -80 degrees C then incubation at 20 degrees C for 1 h under different conditions). Analysis using the nondisruptive probe of sedimentation velocity in the analytical ultracentrifuge indicated that for both antibodies the monomer was always the most common species present whatever storage regime had been used. Sedimentation coefficient distribution analysis showed that other higher oligomer species and half-antibodies were present, and appeared to be not in chemical equilibrium with each other. Solution heterogeneity was found to increase considerably with treatment for both native and hinge-mutant antibodies although the latter appeared to be more resistant to freeze-thaw-induced aggregation.
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Affiliation(s)
- Yanling Lu
- National Centre for Macromolecular Hydrodynamics, University of Nottingham, Sutton Bonington, LE12 5RD, UK
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655
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Wang SSS, Wu JW, Yamamoto S, Liu HS. Diseases of protein aggregation and the hunt for potential pharmacological agents. Biotechnol J 2008; 3:165-92. [DOI: 10.1002/biot.200700065] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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656
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Giteau A, Venier-Julienne M, Aubert-Pouëssel A, Benoit J. How to achieve sustained and complete protein release from PLGA-based microparticles? Int J Pharm 2008; 350:14-26. [DOI: 10.1016/j.ijpharm.2007.11.012] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 11/06/2007] [Accepted: 11/08/2007] [Indexed: 10/22/2022]
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657
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Abstract
Experimental kinetics of non-native protein aggregation are of practical importance in that they help dictate viable processing, formulation, and storage conditions for biotechnology products, and appear to play a role in determining the onset of a number of diseases. Fundamentally, aggregation kinetics provide insights into the identity of key intermediates in the process, and quantitative tests of available models of aggregation. Although aggregation kinetics often display seemingly disparate behaviors across different proteins and sample conditions, this review illustrates how many of these can be understood within a general framework that treats aggregation as a multi-stage process, and how most available kinetic models of aggregation can be grouped hierarchically in terms of which stage(s) they include. This provides an aid for workers seeking a mechanistic interpretation of in vitro aggregation kinetics, for discriminating among competing models, and in designing experiments to assess in vitro protein stability. Limitations and the utility of purely kinetic approaches to studying aggregation, clarifications of common misperceptions regarding experimental aggregation kinetics, and some outstanding challenges in the field are briefly discussed.
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Affiliation(s)
- Christopher J Roberts
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716, USA.
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658
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Andrews JM, Weiss, Roberts CJ. Nucleation, Growth, and Activation Energies for Seeded and Unseeded Aggregation of α-Chymotrypsinogen A. Biochemistry 2008; 47:2397-403. [DOI: 10.1021/bi7019244] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennifer M. Andrews
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
| | - Weiss
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
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659
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Folding Considerations for Therapeutic Protein Formulations. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2008; 83:255-70. [DOI: 10.1016/s0079-6603(08)00606-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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660
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Weiss WF, Hodgdon TK, Kaler EW, Lenhoff AM, Roberts CJ. Nonnative protein polymers: structure, morphology, and relation to nucleation and growth. Biophys J 2007; 93:4392-403. [PMID: 17704182 PMCID: PMC2098717 DOI: 10.1529/biophysj.107.112102] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thermally induced aggregates of alpha-chymotrypsinogen A and bovine granulocyte-colony stimulating factor in acidic solutions were characterized by a combination of static and dynamic light scattering, spectroscopy, transmission electron microscopy, and monomer loss kinetics. The resulting soluble, high-molecular weight aggregates (approximately 10(3)-10(5) kDa) are linear, semiflexible polymer chains that do not appreciably associate with one another under the conditions at which they were formed, with classic power-law scaling of the radius of gyration and hydrodynamic radius with weight-average molecular weight (M(w)). Aggregates in both systems are composed of nonnative monomers with elevated levels of beta-sheet secondary structure, and bind thioflavine T. In general, the aggregate size distributions showed low polydispersity by light scattering. Together with the inverse scaling of M(w) with protein concentration, the results clearly indicate that aggregation proceeds via nucleated (chain) polymerization. For alpha-chymotrypsinogen A, the scaling behavior is combined with the kinetics of aggregation to deduce separate values for the characteristic timescales for nucleation (tau(n)) and growth (tau(g)), as well as the stoichiometry of the nucleus (x). The analysis illustrates a general procedure to noninvasively and quantitatively determine tau(n), tau(g), and x for soluble (chain polymer) aggregates, as well as the relationship between tau(n)/tau(g) and aggregate M(w).
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Affiliation(s)
- William F Weiss
- Department of Chemical Engineering, University of Delaware, Newark, Delaware, USA
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661
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Andrews JM, Roberts CJ. A Lumry-Eyring nucleated polymerization model of protein aggregation kinetics: 1. Aggregation with pre-equilibrated unfolding. J Phys Chem B 2007; 111:7897-913. [PMID: 17571872 DOI: 10.1021/jp070212j] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A mathematical model is presented of the kinetics of non-native protein aggregation that combines Lumry-Eyring and nucleated polymerization (LENP) descriptions. The LENP model is solved for cases in which aggregation rates are slow compared to folding-unfolding equilibration and is shown to be a generalization of a number of previously proposed nucleation-and-growth models for non-native and native protein aggregation. The model solutions exhibit a number of qualitative kinetic regimes. Each regime has a characteristic set of experimental signatures that are related to the relative rates of growth and nucleation as well as to the threshold size at which aggregates condense to form higher-order structures or other phases. Approximate model solutions provide practical rate equations that can be regressed against typical experimental kinetic data to obtain mechanistic parameters characterizing the aggregation pathway. In all kinetic regimes, it is found that observed rate coefficients (kobs) or half-lives (t50) obtained from extent-of-reaction measurements are convolutions of more than one stage in the pathway unless purely seeded growth occurs. Despite this convolution, the combination of apparent reaction order (time domain) and the scaling of kobs or t50 with initial protein concentration provides a means to determine a value for the dominant nucleus size in each case. Additional information, such as equilibrium unfolding thermodynamics and the limiting aggregate size distribution, are required to further deconvolute kobs into intrinsic contributions from nucleation, growth, and conformational changes. The model and analysis are expected to be generally applicable to a wide range of proteins and polypeptides that form non-native aggregates.
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Affiliation(s)
- Jennifer M Andrews
- Department of Chemical Engineering, 150 Academy Street, Colburn Laboratory, University of Delaware, Newark, Delaware 19716, USA
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662
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Groenning M, Olsen L, van de Weert M, Flink JM, Frokjaer S, Jørgensen FS. Study on the binding of Thioflavin T to β-sheet-rich and non-β-sheet cavities. J Struct Biol 2007; 158:358-69. [PMID: 17289401 DOI: 10.1016/j.jsb.2006.12.010] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 12/18/2006] [Accepted: 12/19/2006] [Indexed: 11/27/2022]
Abstract
Amyloid fibril formation plays a role in more than 20 diseases including Alzheimer's disease. In vitro detection of these fibrils is often performed using Thioflavin T (ThT), though the ThT binding mode is largely unknown. In the present study, spectral properties of ThT in binding environments representing beta-sheet-rich and non-beta-sheet cavities were examined. Acetylcholinesterase and gamma-cyclodextrin induced a characteristic ThT fluorescence similar to that with amyloid fibrils, whereas beta-cyclodextrin and the beta-sheet-rich transthyretin did not. The cavities of acetylcholinesterase and gamma-cyclodextrin were of similar diameter and only these cavities could accommodate two ThT ions according to molecular modelling. Binding stoichiometry studies also showed a possible binding of two ThT ions. Thus, the characteristic ThT fluorescence is induced in cavities with a diameter of 8-9A and a length able to accommodate the entire length of the ThT ion. The importance of a cavity diameter capable of binding two ThT ions, among others, indicates that an excimer formation is a plausible mechanism for the characteristic fluorescence. We propose a similar ThT binding mode in amyloid fibrils, where cavities of an appropriate size running parallel to the fibril axis have previously been proposed in several amyloid fibril models.
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Affiliation(s)
- Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
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663
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Vestergaard B, Groenning M, Roessle M, Kastrup JS, van de Weert M, Flink JM, Frokjaer S, Gajhede M, Svergun DI. A helical structural nucleus is the primary elongating unit of insulin amyloid fibrils. PLoS Biol 2007; 5:e134. [PMID: 17472440 PMCID: PMC1858711 DOI: 10.1371/journal.pbio.0050134] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 03/09/2007] [Indexed: 12/31/2022] Open
Abstract
Although amyloid fibrillation is generally believed to be a nucleation-dependent process, the nuclei are largely structurally uncharacterized. This is in part due to the inherent experimental challenge associated with structural descriptions of individual components in a dynamic multi-component equilibrium. There are indications that oligomeric aggregated precursors of fibrillation, and not mature fibrils, are the main cause of cytotoxicity in amyloid disease. This further emphasizes the importance of characterizing early fibrillation events. Here we present a kinetic x-ray solution scattering study of insulin fibrillation, revealing three major components: insulin monomers, mature fibrils, and an oligomeric species. Low-resolution three-dimensional structures are determined for the fibril repeating unit and for the oligomer, the latter being a helical unit composed of five to six insulin monomers. This helical oligomer is likely to be a structural nucleus, which accumulates above the supercritical concentration used in our experiments. The growth rate of the fibrils is proportional to the amount of the helical oligomer present in solution, suggesting that these oligomers elongate the fibrils. Hence, the structural nucleus and elongating unit in insulin amyloid fibrillation may be the same structural component above supercritical concentrations. A novel elongation pathway of insulin amyloid fibrils is proposed, based on the shape and size of the fibrillation precursor. The distinct helical oligomer described in this study defines a conceptually new basis of structure-based drug design against amyloid diseases.
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Affiliation(s)
- Bente Vestergaard
- Department of Medicinal Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Minna Groenning
- Department of Pharmaceutics and Analytical Chemistry, University of Copenhagen, Copenhagen, Denmark
- Biophysics, Novo Nordisk A/S, Bagsvaerd, Denmark
| | - Manfred Roessle
- Hamburg Outstation, European Molecular Biology Laboratory, Hamburg, Germany
| | - Jette S Kastrup
- Department of Medicinal Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Marco van de Weert
- Department of Pharmaceutics and Analytical Chemistry, University of Copenhagen, Copenhagen, Denmark
| | | | - Sven Frokjaer
- Department of Pharmaceutics and Analytical Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Michael Gajhede
- Department of Medicinal Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Dmitri I Svergun
- Hamburg Outstation, European Molecular Biology Laboratory, Hamburg, Germany
- Institute of Crystallography, Russian Academy of Sciences, Moscow, Russia
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664
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Soares AF, Carvalho RDA, Veiga F. Oral administration of peptides and proteins: nanoparticles and cyclodextrins as biocompatible delivery systems. Nanomedicine (Lond) 2007; 2:183-202. [PMID: 17716120 DOI: 10.2217/17435889.2.2.183] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This review discusses drawbacks to peptide and protein oral formulations related to these drugs’ chemical and physical instability. Means used to overcome such limitations are mentioned and discussed in parallel with manufacturing considerations, metabolism, absorption mechanisms and the efflux systems that peptides and proteins experience as they travel through the gastrointestinal tract. Special focus is given to the use of delivery systems based on nanoparticles and cyclodextrins. Advantages of these systems relate to the protection from degradation, enhancement of absorption, targeting and controlling the release of the drug. Biodistribution and safety issues are discussed once material from the delivery system is expected to be absorbed by the body and thus interact with biological components. Operating parameters regarding nanoparticle manufacture and composition are also overviewed since nanoparticle physicochemical characteristics influence the ability to successfully entrap the intended drug as well as interaction with body.
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Affiliation(s)
- Ana Francisca Soares
- Pharmaceutical Technology Laboratory, Faculty of Pharmacy, University of Coimbra, Rua do Norte, 3000-004 Coimbra, Portugal.
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665
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Herrmann S, Mohl S, Siepmann F, Siepmann J, Winter G. New Insight into the Role of Polyethylene Glycol Acting as Protein Release Modifier in Lipidic Implants. Pharm Res 2007; 24:1527-37. [PMID: 17380261 DOI: 10.1007/s11095-007-9271-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 02/12/2007] [Indexed: 11/30/2022]
Abstract
PURPOSE It has recently been shown that the addition of polyethylene glycol 6000 (PEG) to lipidic implants fundamentally affects the resulting protein release kinetics and moreover, the underlying mass transport mechanisms (Herrmann, Winter, Mohl, F. Siepmann, & J. Siepmann, J. Control. Release, 2007). However, it is yet unclear in which way PEG acts. It was the aim of this study to elucidate the effect of PEG in a mechanistic manner. MATERIALS AND METHODS rh-interferon alpha-2a (IFN-alpha)-loaded, tristearin-based implants containing various amounts of PEG were prepared by compression. Protein and PEG release was monitored in phosphate buffer pH 4.0 and pH 7.4. IFN-alpha solubility and stability were assessed by reverse phase and size exclusion HPLC, SDS PAGE, fluorescence and FTIR. RESULTS Importantly, in presence of PEG IFN-alpha was drastically precipitated at pH 7.4. In contrast, at pH 4.0 up to a PEG concentration of 20% no precipitation occurred. These fundamental effects of PEG on protein solubility were reflected in the release kinetics of IFN-alpha from the tristearin implants: At pH 7.4 the protein release rates remained nearly constant over prolonged periods of time, whereas at pH 4.0 high initial bursts and continuously decreasing release rates were observed. Interestingly, it could be shown that IFN-alpha release was governed by pure diffusion at pH 4.0, irrespective of the PEG content of the matrices. In contrast, at pH 7.4 both--the limited solubility of the protein as well as diffusion through tortuous liquid-filled pores--are dominating. CONCLUSIONS For the first time it is shown that the release of pharmaceutical proteins can be controlled by an in-situ precipitation within inert matrices.
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Affiliation(s)
- Sandra Herrmann
- Ludwig-Maximilians-University Munich, Butenandtstr.5, 81377, Munich, Germany.
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666
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Arakawa T, Tsumoto K, Kita Y, Chang B, Ejima D. Biotechnology applications of amino acids in protein purification and formulations. Amino Acids 2007; 33:587-605. [PMID: 17357829 DOI: 10.1007/s00726-007-0506-3] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 01/04/2007] [Indexed: 10/23/2022]
Abstract
Amino acids are widely used in biotechnology applications. Since amino acids are natural compounds, they can be safely used in pharmaceutical applications, e.g., as a solvent additive for protein purification and as an excipient for protein formulations. At high concentrations, certain amino acids are found to raise intra-cellular osmotic pressure and adjust to the high salt concentrations of the surrounding medium. They are called "compatible solutes", since they do not affect macromolecular function. Not only are they needed to increase the osmotic pressure, they are known to increase the stability of the proteins. Sucrose, glycerol and certain amino acids were used to enhance the stability of unstable proteins after isolation from natural environments. The mechanism of the action of these protein-stabilizing amino acids is relatively well understood. On the contrary, arginine was accidentally discovered as a useful reagent for assisting in the refolding of recombinant proteins. This effect of arginine was ascribed to its ability to suppress aggregation of the proteins during refolding, thereby increasing refolding efficiency. By the same mechanism, arginine now finds much wider applications than previously anticipated in the research and development of proteins, in particular in pharmaceutical applications. For example, arginine solubilizes proteins from loose inclusion bodies, resulting in efficient production of active proteins. Arginine suppresses protein-protein interactions in solution and also non-specific adsorption to gel permeation chromatography columns. Arginine facilitates elution of bound proteins from various column resins, including Protein-A or dye affinity columns and hydrophobic interaction columns. This review covers various biotechnology applications of amino acids, in particular arginine.
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Affiliation(s)
- T Arakawa
- Alliance Protein Laboratories, Thousand Oaks, CA, USA.
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667
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Lysozyme particle formation during supercritical fluid drying: Particle morphology and molecular integrity. J Supercrit Fluids 2007. [DOI: 10.1016/j.supflu.2006.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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668
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Aldington S, Bonnerjea J. Scale-up of monoclonal antibody purification processes. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 848:64-78. [PMID: 17224311 DOI: 10.1016/j.jchromb.2006.11.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 11/11/2006] [Accepted: 11/13/2006] [Indexed: 11/22/2022]
Abstract
Mammalian cell culture technology has improved so rapidly over the last few years that it is now commonplace to produce multi-kilogram quantities of therapeutic monoclonal antibodies in a single batch. Purification processes need to be scaled-up to match the improved upstream productivity. In this chapter key practical issues and approaches to the scale-up of monoclonal antibody purification processes are discussed. Specific purification operations are addressed including buffer preparation, chromatography column sizing, aggregate removal, filtration and volume handling with examples given.
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Affiliation(s)
- Suzanne Aldington
- Lonza Biologics, Purification Development, 228 Bath Road, Slough, Berkshire SL1 4DX, UK
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669
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Lee JS, Go DH, Bae JW, Lee SJ, Park KD. Heparin conjugated polymeric micelle for long-term delivery of basic fibroblast growth factor. J Control Release 2007; 117:204-9. [PMID: 17196698 DOI: 10.1016/j.jconrel.2006.11.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 10/31/2006] [Accepted: 11/09/2006] [Indexed: 11/23/2022]
Abstract
Heparin conjugated amphiphilic block copolymer, Tetronic-PCL-heparin (TCH), was developed and its polymeric micelles (PMs) were prepared as an injectable vehicle for long-term delivery of bFGF, which is one of the heparin-binding growth factors (HBGF). TCH PMs were fabricated by a single emulsion and solvent evaporation method. The structural properties of TCH were confirmed by (1)H NMR, FT-IR and GPC. The contents of bound heparin were 0.44 micro g/micro g and the heparin activity by APTT assay was 43.6% when compared to free heparin. The critical micelle concentration (CMC) of TCH PMs was approximately 0.11 g/l. The diameter of TC micelle was approximately 25 nm and its size after conjugation of heparin was increased to 114 nm due to the heparin molecules on the shell of the micelle. The bFGF loading amount of TCH PMs was considerably higher than that of TC, caused by specific interactions between heparin and bFGF. In vitro study, bFGF was released from TCH PMs in a controlled manner over 2 months. The results demonstrated that TCH PMs become a novel candidate for the long-term delivery of various growth factors with heparin-binding domain in tissue engineering.
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Affiliation(s)
- Jung Seok Lee
- Department of Molecular Science and Technology, Ajou University, 5 Wonchon, Yeoungtong, Suwon, South Korea
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670
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Maschke A, Becker C, Eyrich D, Kiermaier J, Blunk T, Göpferich A. Development of a spray congealing process for the preparation of insulin-loaded lipid microparticles and characterization thereof. Eur J Pharm Biopharm 2007; 65:175-87. [PMID: 17070025 DOI: 10.1016/j.ejpb.2006.08.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 08/01/2006] [Accepted: 08/08/2006] [Indexed: 11/30/2022]
Abstract
A spray congealing process for the preparation of protein-loaded microparticles was developed. The influence of the process parameters atomization pressure and spraying temperature on particle size and process yield was investigated by experimental design. The employed spray congealing technique enabled the production of microparticles with yields ranging from 79% to 95% and median particle sizes (d(0.5)) from 182.2 to 315 microm. Insulin lipid microparticles could be prepared without any loss of insulin during the preparation process and the protein stability was not affected by the spray congealing process as investigated by HPLC-MS analysis. The stability of insulin encapsulated in lipid microparticles under release conditions over 28 days was assessed by investigating the residual insulin content. Starting after 3 days of release, a continuous increase of desamidoinsulin in the remaining particles of up to 7.5% after 28 days was observed. An additional degradation product was detected by HPLC and HPLC-MS analysis and identified as a covalent insulin dimer by MALDI-ToF. The microparticles did not show a burst release and testing the insulin lipid microparticles in a fibrin gel chondrocyte culture revealed that the released insulin was bioactive and had a significant effect on chondrocyte extracellular matrix production.
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Affiliation(s)
- Angelika Maschke
- Department of Pharmaceutical Technology, University of Regensburg, 93040 Regensburg, Germany
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671
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Mezzasalma TM, Kranz JK, Chan W, Struble GT, Schalk-Hihi C, Deckman IC, Springer BA, Todd MJ. Enhancing Recombinant Protein Quality and Yield by Protein Stability Profiling. ACTA ACUST UNITED AC 2007; 12:418-28. [PMID: 17438070 DOI: 10.1177/1087057106297984] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The reliable production of large amounts of stable, high-quality proteins is a major challenge facing pharmaceutical protein biochemists, necessary for fulfilling demands from structural biology, for high-throughput screening, and for assay purposes throughout early discovery. One strategy for bypassing purification challenges in problematic systems is to engineer multiple forms of a particular protein to optimize expression, purification, and stability, often resulting in a nonphysiological sub-domain. An alternative strategy is to alter process conditions to maximize wild-type construct stability, based on a specific protein stability profile (PSP). ThermoFluor®, a miniaturized 384-well thermal stability assay, has been implemented as a means of monitoring solution-dependent changes in protein stability, complementing the protein engineering and purification processes. A systematic analysis of pH, buffer or salt identity and concentration, biological metals, surfactants, and common excipients in terms of an effect on protein stability rapidly identifies conditions that might be used (or avoided) during protein production. Two PSPs are presented for the kinase catalytic domains of Akt-3 and cFMS, in which information derived from a ThermoFluor® PSP led to an altered purification strategy, improving the yield and quality of the protein using the primary sequences of the catalytic domains. ( Journal of Biomolecular Screening 2007:418-428)
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Affiliation(s)
- Tara M Mezzasalma
- Johnson & Johnson Pharmaceutical Research & Development, LLC, Exton, Pennsylvania 19341, USA
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672
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Yu LC, Chen SC, Chang WC, Huang YC, Lin KM, Lai PH, Sung HW. Stability of angiogenic agents, ginsenoside Rg1 and Re, isolated from Panax ginseng: In vitro and in vivo studies. Int J Pharm 2007; 328:168-76. [PMID: 16962729 DOI: 10.1016/j.ijpharm.2006.08.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 05/18/2006] [Accepted: 08/08/2006] [Indexed: 11/22/2022]
Abstract
The study was designed to investigate the stability of ginsenoside Rg(1) (Rg(1)) and Re (Re), two natural herbal compounds isolated from Panax ginseng, based on their activity to promote angiogenesis in vitro and in vivo. After being treated at different temperatures, pHs, and solvent species for distinct durations, the remaining activities of Rg(1) and Re on human umbilical vein endothelial cell (HUVEC) proliferation, migration, and tube formation were examined in vitro. Additionally, the remaining activity of each treated test agent, mixed in a growth factor-reduced Matrigel, in stimulating angiogenesis was evaluated subcutaneously in a mouse model. Basic fibroblast growth factor (bFGF) was used as a control. It was found in vitro that HUVEC proliferation, migration in a Transwell plate, and tube formation on Matrigel were all significantly enhanced in the presence of bFGF, Rg(1), or Re. However, after being treated at different temperatures, pHs, or solvent species, the remaining activity of bFGF on HUVEC behaviors reduced significantly. This observation was more significant with increasing the duration of treatment. In contrast, the activities of Rg(1) and Re remained unchanged throughout the entire course of the study. The in vivo results observed on day 7 after implantation showed that the blank control (Matrigel alone) was slightly vascularized. In contrast, the density of neo-vessels in the Matrigel plug mixed with bFGF, Rg(1), or Re was significantly enhanced. However, after being treated, the density of neo-vessels was significantly reduced in the Matrigel plug mixed with bFGF, while those of Rg(1) and Re remained unchanged. The aforementioned results suggested that Rg(1) and Re could be a novel group of nonpeptide angiogenic agents with a superior stability and may be used for the management of tissue regeneration.
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Affiliation(s)
- Lin-Chien Yu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC
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673
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Tavornvipas S, Hirayama F, Takeda S, Arima H, Uekama K. Effects of Cyclodextrins on Chemically and Thermally Induced Unfolding and Aggregation of Lysozyme and Basic Fibroblast Growth Factor. J Pharm Sci 2006; 95:2722-9. [PMID: 16917853 DOI: 10.1002/jps.20715] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Effects of cyclodextrin (CyDs) on unfolding and aggregation of lysozyme and basic fibroblast growth factor (bFGF) were investigated. CyDs inhibited the chemically induced aggregation and its inhibition was generally in the order of gamma-CyDs < alpha-CyDs < beta-CyDs. Among these CyDs, branched beta-CyDs and dimethyl-beta-CyD (DM-beta-CyD) significantly reduced the aggregation of lysozyme. Hydrophilic CyDs reduced the thermally induced unfolding of lysozyme as shown by a decrease in the thermal unfolding temperature (T(m)) value of lysozyme, suggesting that CyDs destabilize native lysozyme or stabilize the unfolded state of lysozyme. In the case of bFGF, branched beta-CyDs showed greater effects on inhibition of the chemically and thermally induced denaturation. Interestingly, sulfobutyl ether beta-CyD (SBE-beta-CyD), which was not effective in case of lysozyme, provided the inhibitory effect for bFGF on the chemically, thermally and acid-induced denaturation, suggesting that both the inclusion and electrostatic interaction may be operative in the inhibition of aggregation of the positively charged protein. The results indicated that the use of CyDs for protein stabilization is dependent not only on the structure and property of CyDs but also on the nature of the denaturing stimuli, and the most appropriate CyD should be used for the stabilization of each protein.
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Affiliation(s)
- Sumitra Tavornvipas
- Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
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674
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Maas C, Hermeling S, Bouma B, Jiskoot W, Gebbink MFBG. A role for protein misfolding in immunogenicity of biopharmaceuticals. J Biol Chem 2006; 282:2229-36. [PMID: 17135263 DOI: 10.1074/jbc.m605984200] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For largely unknown reasons, biopharmaceuticals evoke potentially harmful antibody formation. Such antibodies can inhibit drug efficacy and, when directed against endogenous proteins, cause life-threatening complications. Insight into the mechanisms by which biopharmaceuticals break tolerance and induce an immune response will contribute to finding solutions to prevent this adverse effect. Using a transgenic mouse model, we here demonstrate that protein misfolding, detected with the use of tissue-type plasminogen activator and thioflavin T, markers of amyloid-like properties, results in breaking of tolerance. In wild-type mice, misfolding enhances protein immunogenicity. Several commercially available biopharmaceutical products were found to contain misfolded proteins. In some cases, the level of misfolded protein was found to increase upon storage under conditions prescribed by the manufacturer. Our results indicate that misfolding of therapeutic proteins is an immunogenic signal and a risk factor for immunogenicity. These findings offer novel possibilities to detect immunogenic protein entities with tPA and reduce immunogenicity of biopharmaceuticals.
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Affiliation(s)
- Coen Maas
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Center Utrecht and the Institute for Biomembranes, Padualaan 8, 3584 CH Utrecht, The Netherlands
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675
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Capelle MAH, Gurny R, Arvinte T. High throughput screening of protein formulation stability: practical considerations. Eur J Pharm Biopharm 2006; 65:131-48. [PMID: 17107777 DOI: 10.1016/j.ejpb.2006.09.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 09/01/2006] [Accepted: 09/18/2006] [Indexed: 11/28/2022]
Abstract
The formulation of protein drugs is a difficult and time-consuming process, mainly due to the complexity of protein structure and the very specific physical and chemical properties involved. Understanding protein degradation pathways is essential for the success of a biopharmaceutical drug. The present review concerns the application of high throughput screening techniques in protein formulation development. A protein high throughput formulation (HTF) platform is based on the use of microplates. Basically, the HTF platform consists of two parts: (i) sample preparation and (ii) sample analysis. Sample preparation involves automated systems for dispensing the drug and the formulation ingredients in both liquid and powder form. The sample analysis involves specific methods developed for each protein to investigate physical and chemical properties of the formulations in microplates. Examples are presented of the use of protein intrinsic fluorescence for the analysis of protein aqueous properties (e.g., conformation and aggregation). Different techniques suitable for HTF analysis are discussed and some of the issues concerning implementation are presented with reference to the use of microplates.
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Affiliation(s)
- Martinus A H Capelle
- Department of Pharmaceutics and Biopharmaceutics, University of Geneva, University of Lausanne, CH-1211 Geneva 4, Switzerland
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676
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Berkowitz SA. Role of analytical ultracentrifugation in assessing the aggregation of protein biopharmaceuticals. AAPS J 2006; 8:E590-605. [PMID: 17025277 PMCID: PMC2761066 DOI: 10.1208/aapsj080368] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 06/22/2006] [Indexed: 11/30/2022] Open
Abstract
In developing and manufacturing protein biopharmaceuticals, aggregation is a parameter that needs careful monitoring to ensure the quality and consistency of the final biopharmaceutical drug product. The analytical method of choice used to perform this task is size-exclusion chromatography (SEC). However, it is becoming more and more apparent that considerable care is required in assessing the accuracy of SEC data. One old analytical tool that is now reappearing to help in this assessment is analytical ultracentrifugation (AUC). Developments in AUC hardware and, more importantly, recent developments in AUC data analysis computer programs have converged to provide this old biophysical tool with the ability to extract very high resolution size information about the molecules in a given sample from a simple sedimentation velocity experiment. In addition, AUC allows sample testing to be conducted in the exact or nearly exact liquid formulation or reconstituted liquid formulation of the biopharmaceutical in the vial, with minimal surface area contact with extraneous materials. As a result, AUC analysis can provide detailed information on the aggregation of a biopharmaceutical, while avoiding many of the major problems that can plague SEC, thus allowing AUC to be used as an orthogonal method to verify SEC aggregation information and the associating properties of biopharmaceuticals.
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Affiliation(s)
- Steven A Berkowitz
- Department of Analytical Development, Biogen Idec Inc, 14 Cambridge Center, Cambridge, MA 02142, USA.
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677
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Zanier K, Nominé Y, Charbonnier S, Ruhlmann C, Schultz P, Schweizer J, Travé G. Formation of well-defined soluble aggregates upon fusion to MBP is a generic property of E6 proteins from various human papillomavirus species. Protein Expr Purif 2006; 51:59-70. [PMID: 17055740 DOI: 10.1016/j.pep.2006.07.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 06/27/2006] [Accepted: 07/03/2006] [Indexed: 10/24/2022]
Abstract
Protein aggregation is a main barrier hindering structural and functional studies of a number of interesting biological targets. The E6 oncoprotein of Human Papillomavirus strain 16 (E6(16)) is difficult to express under a native soluble form in bacteria. Produced as an unfused sequence, it forms inclusion bodies. Fused to the C-terminus of MBP, it is mainly produced in the form of soluble high molecular weight aggregates. Here, we produced as MBP-fusions seven E6 proteins from other HPV strains (5, 11, 18, 33, 45, 52, and 58) belonging to four different species, and we compared their aggregation state to that of MBP-E6(16). Using a fast mutagenesis method, we changed most non-conserved cysteines to the isosteric residue serine to minimize disulfide bridge-mediated aggregation during purification. Static and dynamic light scattering measurements, ultracentrifugation and electron microscopy demonstrated the presence in all MBP-E6 preparations of soluble high-molecular weight aggregates with a well-defined spherical shape. These aggregated particles are relatively monodisperse but their amount and their size vary depending on the conditions of expression and the strain considered. For all strains, minimal aggregate formation occurs when the expression is performed at 15 degrees C. Such observations suggest that the assembly of MBP-E6 aggregates takes place in vivo during protein biosynthesis, rather than occurring during purification. Finally, we show that all MBP-E6 preparations contain two zinc ions per protein monomer, suggesting that E6 domains within the high molecular weight aggregates possess a native-like fold, which enables correct coordination to the metal center.
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Affiliation(s)
- Katia Zanier
- Ecole Supérieure de Biotechnologie de Strasbourg, Institut Gilbert Laustriat (UMR 7175 LC1), Boulevard Sébastien Brant, BP 10413, 67412 Illkirch, France
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678
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Bao X, Isaacsohn I, Drew AF, Smithrud DB. Determining the Intracellular Transport Mechanism of a Cleft−[2]Rotaxane. J Am Chem Soc 2006; 128:12229-38. [PMID: 16967974 DOI: 10.1021/ja063667f] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rotaxanes are a class of interlocked compounds that have been extensively investigated for their potential utility as switches or sensors. We recently demonstrated that rotaxanes have further application as agents that transport material into cells. This novel finding prompted our investigation into the mechanism by which rotaxanes are involved in transmembrane transport. Two-dimensional NMR analysis showed that a cleft-containing rotaxane exists in two dominant conformations ("closed" and "open"). To determine the importance of conformational flexibility on the ability of the rotaxanes to bind guests and transport material into cells, the rotaxane was chemically modified to lock it in the closed conformation. Charged guests interact less favorably with the locked rotaxane, as compared to the unmodified rotaxane, both in an aqueous solution and in DMSO. In a chloroform solution, both rotaxanes bind the guests with similar affinities. The locked rotaxane exhibited a reduced capacity to transport a fluoresceinated peptide into cells, whereas the unmodified rotaxane efficiently delivers the peptide. Flow cytometry experiments demonstrated that a high percentage of the cells contained the delivered peptide (89-98%), the level of delivery is concentration dependent, and the rotaxanes and peptide have low toxicity. Cellular uptake of the peptide was largely temperature and ATP independent, suggesting that the rotaxane-peptide complex passes through the cellular membrane without requiring active cell-mediated processes. The results show that the sliding motion of the wheel is necessary for the delivery of materials into cells and can enhance the association of guests. These studies demonstrate the potential for rotaxanes as a new class of mechanical devices that deliver a variety of therapeutic agents into targeted cell populations.
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Affiliation(s)
- Xiaofeng Bao
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
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679
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Oates KM, Krause WE, Jones RL, Colby RH. Rheopexy of synovial fluid and protein aggregation. J R Soc Interface 2006; 3:167-74. [PMID: 16849228 PMCID: PMC1618490 DOI: 10.1098/rsif.2005.0086] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bovine synovial fluid and albumin solutions of similar concentration are rheopectic (stress increases with time in steady shear). This unusual flow characteristic is caused by protein aggregation, and the total stress is enhanced by entanglement of this tenuous protein network with the long-chain polysaccharide sodium hyaluronate under physiological conditions. Neutron scattering measurements on albumin solutions demonstrate protein aggregation and all measurements are consistent with a weak dipolar attraction energy (of order 3kT) that is most likely augmented by hydrophobic interactions and/or disulfide bond formation between proteins. Protein aggregation appears to play an important role in the mechanical properties of blood and synovial fluid. We also suggest a connection between the observed rheopexy and the remarkable lubrication properties of synovial fluid.
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Affiliation(s)
- Katherine M.N Oates
- Department of Materials Science and Engineering and the Materials Research Institute, The Pennsylvania State UniversityUniversity Park, PA 16802, USA
| | - Wendy E Krause
- Department of Textile Engineering, Chemistry and Science, North Carolina State UniversityRaleigh, NC 27695, USA
| | | | - Ralph H Colby
- Department of Materials Science and Engineering and the Materials Research Institute, The Pennsylvania State UniversityUniversity Park, PA 16802, USA
- Author for correspondence ()
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680
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Cirpus IEY, Geerts W, Hermans JHM, Op den Camp HJM, Strous M, Kuenen JG, Jetten MSM. Challenging protein purification from anammox bacteria. Int J Biol Macromol 2006; 39:88-94. [PMID: 16580723 DOI: 10.1016/j.ijbiomac.2006.02.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 02/15/2006] [Accepted: 02/15/2006] [Indexed: 11/19/2022]
Abstract
The anaerobic ammonium oxidation (anammox) is a fascinating microbial pathway contributing to the global biogeochemical nitrogen cycle. The anammox pathway of nitrogen conversion can only be elucidated after the responsible proteins have been purified and characterised. The anammox bacteria have a complex cell envelope consisting of protein and lipopolysaccharide and they grow in dense cell aggregates. Preparing cell extract and purifying proteins from the cell aggregates is hampered by the extracellular polymeric material and by gel formation. It was demonstrated that protein-protein (i.e. disulfide formation) as well as protein-polysaccharide interaction caused this gel formation in extracts. Cell extract gelled upon freezing/thawing and boiling. Additionally, proteins aggregated on various chromatography media upon concentration and during desalting. The polysaccharides clogged the matrix of chromatographic materials and the pores of ultrafiltration membranes. The precipitation of proteins and polysaccharides caused very low resolution and streaking on SDS- and two-dimensional polyacrylamide gels. The present work describes the potential causes for gel formation in anammox cell extracts. Optimized protocols for sample preparation for polyacrylamide gel electrophoresis and ion exchange chromatography are presented. High-resolution gel electrophoresis of the cell extract was achieved after clarification from polymeric substances with denaturating phenol extraction and the purification of a 10 kDa cytochrome c is presented as an example.
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Affiliation(s)
- Irina E Y Cirpus
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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681
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Kim SG, Kim JA, Yu HA, Lee DH, Kweon DH, Seo JH. Application of poly-arginine fused minichaperone to renaturation of cyclodextrin glycosyltransferase expressed in recombinant Escherichia coli. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2005.11.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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682
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De Jong KL, Incledon B, Yip CM, DeFelippis MR. Amyloid fibrils of glucagon characterized by high-resolution atomic force microscopy. Biophys J 2006; 91:1905-14. [PMID: 16766610 PMCID: PMC1544305 DOI: 10.1529/biophysj.105.077438] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glucagon solutions at pH 2.0 were subjected to mechanical agitation at 37 degrees C in the presence of a hydrophobic surface to explore the details of aggregation and fiber formation. High-resolution intermittent-contact atomic force microscopy performed in solution revealed the presence of aggregates after 0.5 h; however, longer agitation times resulted in the formation of fibrillated structures with varying levels of higher-order assembly. Height, periodicity, and amplitude measurements of these structures allowed the identification of four distinct fiber types. The most elementary fiber form, designated a filament, self-associates in a specific wound fashion to produce protofibrils composed of two filaments. Subsequent self-assembly of these filaments and protofibrils leads to two well-defined fibrillar motifs, termed Type I and Type II. Atomic force microscopy imaging of pH 2.8 glucagon solutions not agitated or exposed to elevated temperature revealed the presence of amorphous aggregates before the formation of fibrillar structures similar to those seen at pH 2.0. Time-course solution Fourier transform infrared spectroscopy and thioflavin T binding studies suggested that glucagon aggregation and fibril formation were associated with the development of beta-sheet structure. The results of these studies are used to describe a possible mechanism for glucagon aggregation and fibrillation that is consistent with a hierarchical assembly model proposed for amyloid fibril formation.
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Affiliation(s)
- Kathy L De Jong
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA
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683
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Gorbenko GP, Kinnunen PKJ. The role of lipid–protein interactions in amyloid-type protein fibril formation. Chem Phys Lipids 2006; 141:72-82. [PMID: 16569401 DOI: 10.1016/j.chemphyslip.2006.02.006] [Citation(s) in RCA: 221] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 02/20/2006] [Indexed: 11/29/2022]
Abstract
Structural transition of polypeptide chains into the beta-sheet state followed by amyloid fibril formation is the key characteristic of a number of the so-called conformational diseases. The multistep process of protein fibrillization can be modulated by a variety of factors, in particular by lipid-protein interactions. A wealth of experimental evidence provides support to the notion that amyloid fibril assembly and the toxicity of pre-fibrillar aggregates are closely related and are both intimately membrane associated phenomena. The present review summarizes the principal factors responsible for the enhancement of fibril formation in a membrane environment, viz. (i) structural transformation of polypeptide chain into a partially folded conformation, (ii) increase of the local concentration of a protein upon its membrane binding, (iii) aggregation-favoring orientation of the bound protein, and (iv) variation in the depth of bilayer penetration affecting the nucleation propensity of the membrane associated protein. The molecular mechanisms of membrane-mediated protein fibrillization are discussed. Importantly, the toxicity of lipid-induced pre-fibrillar aggregates is likely to have presented a very strong negative selection pressure in the evolution of amino acid sequences.
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Affiliation(s)
- Galyna P Gorbenko
- Department of Biological and Medical Physics, VN Karazin Kharkiv National University, Ukraine
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684
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Matheus S, Friess W, Mahler HC. FTIR and nDSC as analytical tools for high-concentration protein formulations. Pharm Res 2006; 23:1350-63. [PMID: 16715365 DOI: 10.1007/s11095-006-0142-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE The aim of the study is to evaluate Fourier-transform infrared spectroscopy (FTIR) as an analytical tool for high-concentrated protein formulations. METHODS FTIR is used to determine the melting temperature (T(m (FTIR))) of various proteins, such as bovine serum albumin (BSA), immunoglobulin (IgG1), beta-lactoglobulin (beta-LG), and lysozyme (HEWL), at different protein concentrations (5-100 mg/mL), where four data interpretation methods are discussed. The obtained T(m (FTIR)) values are further compared to the T(m) measured by the nanodifferential scanning calorimetry (nDSC) technique. RESULTS The T(m (FTIR)) values of IgG1 and beta-LG showed strong consistency and corresponded to the nDSC results irrespective of the method of data interpretation and the protein concentration applied. In contrast, the T(m (FTIR)) of BSA and HEWL is characterized by significant deviations. Only the midpoint of the second-derivative intensity-temperature curve of the intermolecular beta-sheet mode measured at a concentration of 100 mg/mL is consistent with the nDSC results. CONCLUSIONS Determination of a T(m (FTIR)) is feasible by the midpoint of the intensity-temperature plot of the arising intermolecular beta-sheet band. More significant results are obtained for proteins, which are predominantly composed of intramolecular beta-sheet elements as well as at higher protein concentrations. A further study was started to assess the predictability of long-term protein stability by T(m (FTIR)).
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Affiliation(s)
- Susanne Matheus
- Merck KGaA, Global Pharmaceutical Development, Darmstadt, Germany
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685
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Guo S, Akhremitchev BB. Packing Density and Structural Heterogeneity of Insulin Amyloid Fibrils Measured by AFM Nanoindentation. Biomacromolecules 2006; 7:1630-6. [PMID: 16677048 DOI: 10.1021/bm0600724] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A nanoindentation approach based on atomic force microscopy was applied to test the elastic properties of insulin amyloid fibrils. Fibrils exhibited a nearly elastic response to the compressive load. The results, corrected for the finite sample thickness effect, reveal that the fibril Young's modulus is considerably lower than the modulus of protein crystals, suggesting lower packing density in amyloid fibrils. Variation in elasticity among and within fibrils has been studied, showing that the Young's moduli of insulin fibrils have a relatively wide distribution of values, ranging from 5 to 50 MPa. Amyloid fibrils with higher modulus were found to be more wear-resistant during AFM scanning. The measured distribution of elasticity values of different fibrils together with wear-resistance tests indicates structural heterogeneity among fibrils, whereas the structure of individual fibrils appears to be homogeneous. The relative simplicity of the method used in this study can facilitate rapid collection of quantitative information related to the packing density and heterogeneity of fibrils formed by different proteins.
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Affiliation(s)
- Senli Guo
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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686
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Zheng JY, Janis LJ. Influence of pH, buffer species, and storage temperature on physicochemical stability of a humanized monoclonal antibody LA298. Int J Pharm 2006; 308:46-51. [PMID: 16316730 DOI: 10.1016/j.ijpharm.2005.10.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Revised: 10/10/2005] [Accepted: 10/10/2005] [Indexed: 11/22/2022]
Abstract
The purpose of this work is to study the effect of pH, buffer species, and temperature on the physicochemical stability of a humanized monoclonal antibody LA298. The study was carried out in solution state of the antibody in the presence of different buffer species at different pH values and storage temperature. No significant changes in total protein content were observed for any of the solutions with different buffers at different pH values when stored for 8 weeks at both 5 degrees C and 25 degrees C or at 37 degrees C for 1 week. Known asparagines (Asn55) deamidation of LA298 was found to be dependent on pH, buffer type, and temperature. The estimated rate constant of the double heavy chain Asn55 deamidation in phosphate buffer at pH 6.5 and 7.0 was much higher than that in citrate buffer under the same storage conditions. However, comparable results were obtained for single heavy chain Asn55 deamidation in citrate and phosphate buffer. Aggregation of LA298 was not significant for samples at different pH values, buffers, and temperatures as the monomer of LA298 decreased dramatically over time. Less decrease in monomeric LA298 was observed in citrate buffer, pH 5.0-5.5. In conclusion, to minimize deamidation and loss of LA298 monomer, it is important to optimize its solution pH, buffer species, and storage temperature.
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Affiliation(s)
- Jack Y Zheng
- Pharmaceutical Sciences R&D, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
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687
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Pedersen S, Nesgaard L, Baptista RP, Melo EP, Kristensen SR, Otzen DE. pH-dependent aggregation of cutinase is efficiently suppressed by 1,8-ANS. Biopolymers 2006; 83:619-29. [PMID: 16964599 DOI: 10.1002/bip.20598] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have studied the thermal stability of the triglyceride-hydrolyzing enzyme cutinase from F. solani pisi at pH values straddling the pI (pH 8.0). At the pI, increasing the protein concentration from 5 to 80 microM decreases the apparent melting temperature by 19 degrees C. This effect vanishes at pH values more than one unit away from pI. In contrast to additives such as detergents and osmolytes, the hydrophobic fluorophore 1,8-ANS completely and saturably suppresses this effect, restoring 70% of enzymatic activity upon cooling. ANS binds strongly to native cutinase as a noncompetitive inhibitor with up to 5 ANS per cutinase molecule. Only the first ANS molecule stabilizes cutinase; however, the last 4 ANS molecules decrease Tm by up to 7 degrees C. Similar pI-dependent aggregation and suppression by ANS is observed for T. lanuginosus lipase, but not for lysozyme or porcine alpha-amylase, suggesting that this behavior is most prevalent for proteins with affinity for hydrophobic substrates and consequent exposure of hydrophobic patches. Aggregation may be promoted by a fluctuating ensemble of native-like states associating via intermolecular beta-sheet rich structures unless blocked by ANS. Our data highlight the chaperone activity of small molecules with affinity for hydrophobic surfaces and their potential application as stabilizers at appropriate stoichiometries.
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Affiliation(s)
- Shona Pedersen
- Department of Life Sciences, Aalborg University, DK-9000 Aalborg, Denmark
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688
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Pedersen JS, Dikov D, Flink JL, Hjuler HA, Christiansen G, Otzen DE. The changing face of glucagon fibrillation: structural polymorphism and conformational imprinting. J Mol Biol 2005; 355:501-23. [PMID: 16321400 DOI: 10.1016/j.jmb.2005.09.100] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2005] [Revised: 07/15/2005] [Accepted: 09/13/2005] [Indexed: 11/17/2022]
Abstract
We have established a time-resolved fluorescence assay to study fibrillation of the 29 residue peptide hormone glucagon under a variety of different conditions in a high-throughput format. Fibrils formed at pH 2.5 differ in fibrillation kinetics, morphology, thioflavin T staining and FTIR/CD spectra depending on salts, glucagon concentration and fibrillation temperature. Apparent fibrillar stability correlates with spectral and kinetic properties; generally, fibrils formed under conditions favourable for rapid fibrillation (ambient temperatures, high glucagon concentration or high salt concentration) appear less thermostable than those formed under more challenging conditions (high temperatures, low glucagon or low salt concentrations). Properties of preformed fibrils used for seeding are inherited in a prion-like manner. Thus, we conclude that the structure of fibrils formed by glucagon is not the result of the global energy minimization, but rather kinetically controlled by solvent conditions and seed-imprinting. Fibrillar polymorphism, which is being reported for an increasing number of proteins, probably reflects that fibrils have not been under evolutionary constraints to retain a single active conformation. Our results highlight the complexity of the fibrillation mechanism of glucagon, since even subtle changes in fibrillation conditions can alter the type of fibrils formed, or result in formation of mixtures of several types of fibrils.
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689
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Abstract
The increasing use of recombinantly expressed therapeutic proteins in the pharmaceutical industry has highlighted issues such as their stability during long-term storage and means of efficacious delivery that avoid adverse immunogenic side effects. Controlled chemical modifications, such as substitutions, acylation and PEGylation, have fulfilled some but not all of their promises, while hydrogels and lipid-based formulations could well be developed into generic delivery systems. Strategies to curb the aggregation and misfolding of proteins during storage are likely to benefit from the recent surge of interest in protein fibrillation. This might in turn lead to generally accepted guidelines and tests to avoid unforeseen adverse effects in drug delivery.
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Affiliation(s)
- Sven Frokjaer
- Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen O, Denmark
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