The Experts below are selected from a list of 11601 Experts worldwide ranked by ideXlab platform
Gianfranco Pasut - One of the best experts on this subject based on the ideXlab platform.
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Chemical and Enzymatic Site Specific PEGylation of hGH
Bioconjugate chemistry, 2013Co-Authors: Débora Da Silva Freitas, Anna Mero, Gianfranco PasutAbstract:Several strategies for site-specific PEGylation have been successfully exploited to conjugate poly(ethylene glycol) (PEG) to pharmaceutical proteins. The advantages sought are those of improving efficacy and increasing the half-life of conjugated proteins while achieving a higher degree of homogeneity. Recombinant human growth hormone (hGH) was thus PEGylated exploiting two site-specific strategies: N-terminal PEGylation using the PEG20 kDa–aldehyde polymer and microbial transglutaminase (mTGase) mediated enzymatic PEGylation using PEG20 kDa–NH2. N-Terminal PEGylation of hGH was carried out by covalent attachment of PEG to the α-amine residue of Phe1 that yielded the monoconjugate PEG-Nter-hGH with a mass of 44152.2 Da, as measured by MALDI-TOF mass spectrometry. The mTGase mediated PEGylation, performed in a water/ethanol solution mixture, allowed a PEG coupling reaction only at the level of hGH Gln141, yielding the single monoconjugate PEG-Gln141-hGH with a mass of 44064.9 Da. Circular dichroism studies...
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State of the art in PEGylation: the great versatility achieved after forty years of research.
Journal of controlled release : official journal of the Controlled Release Society, 2011Co-Authors: Gianfranco Pasut, Francesco M. VeroneseAbstract:Abstract In the recent years, protein PEGylation has become an established and highly refined technology by moving forward from initial simple random coupling approaches based on conjugation at the level of lysine e-amino group. Nevertheless, amino PEGylation is still yielding important conjugates, currently in clinical practice, where the degree of homogeneity was improved by optimizing the reaction conditions and implementing the purification processes. However, the current research is mainly focused on methods of site-selective PEGylation that allow the obtainment of a single isomer, thus highly increasing the degree of homogeneity and the preservation of bioactivity. Protein N-terminus and free cysteines were the first sites exploited for selective PEGylation but currently further positions can be addressed thanks to approaches like bridging PEGylation (disulphide bridges), enzymatic PEGylation (glutamines and C-terminus) and glycoPEGylation (sites of O- and N-glycosylation or the glycans of a glycoprotein). Furthermore, by combining the tools of genetic engineering with specific PEGylation approaches, the polymer can be basically coupled at any position on the protein surface, owing to the substitution of a properly chosen amino acid in the sequence with a natural or unnatural amino acid bearing an orthogonal reactive group. On the other hand, PEGylation has not achieved the same success in the delivery of small drugs, despite the large interest and several studies in this field. Targeted conjugates and PEGs for combination therapy might represent the promising answers for the so far unmet needs of PEG as carrier of small drugs. This review presents a thorough panorama of recent advances in the field of PEGylation.
Zhong-xing Jiang - One of the best experts on this subject based on the ideXlab platform.
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Monodisperse and Polydisperse PEGylation of Peptides and Proteins: A Comparative Study.
Biomacromolecules, 2020Co-Authors: Jie Wang, Zhigang Yang, Tao Deng, Yuntai Liu, Kexin Chen, Zhong-xing JiangAbstract:Although PEGylation is widely used in biomedicine with great success, it suffers from many drawbacks, such as polydispersity, nonbiodegradability, and loss of precursor potency. Recently, the search for polyethylene glycol (PEG) substitutes has attracted considerable attention. Some of the substitutes partially address the drawbacks of PEGs, but sacrifice the "stealth" effect of PEGs and bring in new issues. Herein, we developed monodisperse oligoethylene glycol (M-OEG) polyamides over 5000 Da as biodegradable and monodisperse PEGylation (M-PEGylation) agents, which provided M-PEGylated peptides and proteins with high monodispersity and a biodegradable PEG moiety. Compared to regular PEGylated proteins with a complex "stealth" cloud of PEG, the hydrogen bond interactions between the M-OEG polyamides and proteins provided the M-PEGylated protein with a biodegradable "stealth" cloak. The monodisperse and biodegradable M-PEGylation strategy as well as the peculiar protein-M-OEG polyamide interactions may shed light on many long-lasting issues during the development of PEGylated biologic drugs, such as monodispersity, biodegradability, and tunable conformation.
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Quantitatively Fine-Tuning the Physicochemical and Biological Properties of Peptidic Polymers through Monodisperse PEGylation
Biomacromolecules, 2020Co-Authors: Xuemeng Wang, Zhigang Yang, Xing Zheng, Shizhen Chen, Xin Zhou, Zhong-xing JiangAbstract:In biomedicine, PEGylation is one of the most successful strategies to modify the physicochemical and biological properties of peptides, proteins, and other biomacromolecules. Because of the polydisperse nature of regular PEGs and limited PEGylation strategies, it is challenging to quantitatively fine-tune and accurately predict the properties of biomacromolecules after PEGylation. However, such fine-tuning and prediction may be crucial for their biomedical applications. Herein, some monodisperse PEGylation strategies, including backbone PEGylation, side-chain PEGylation, and highly branched PEGylation, have been developed. In a comparative fashion, the impact of PEGylation strategies and monodisperse PEG sizes on the physicochemical and biological properties, including lipophilicity, thermosensitivity, biocompatibility, plasma stability, and drug delivery capability, of peptidic polymers has been quantitatively studied. It was found that the physicochemical and biological properties of PEGylated peptidic...
Mark D Distefano - One of the best experts on this subject based on the ideXlab platform.
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Site-Specific PEGylation of Therapeutic Proteins
International Journal of Molecular Sciences, 2015Co-Authors: Jonathan K Dozier, Mark D DistefanoAbstract:The use of proteins as therapeutics has a long history and is becoming ever more common in modern medicine. While the number of protein-based drugs is growing every year, significant problems still remain with their use. Among these problems are rapid degradation and excretion from patients, thus requiring frequent dosing, which in turn increases the chances for an immunological response as well as increasing the cost of therapy. One of the main strategies to alleviate these problems is to link a polyethylene glycol (PEG) group to the protein of interest. This process, called PEGylation, has grown dramatically in recent years resulting in several approved drugs. Installing a single PEG chain at a defined site in a protein is challenging. Recently, there is has been considerable research into various methods for the site-specific PEGylation of proteins. This review seeks to summarize that work and provide background and context for how site-specific PEGylation is performed. After introducing the topic of site-specific PEGylation, recent developments using chemical methods are described. That is followed by a more extensive discussion of bioorthogonal reactions and enzymatic labeling.
Guifeng Zhang - One of the best experts on this subject based on the ideXlab platform.
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Kinetic and stoichiometric analysis of the modification process for N-terminal PEGylation of staphylokinase.
Analytical biochemistry, 2010Co-Authors: Jun Wang, Yongdong Liu, Guifeng ZhangAbstract:Staphylokinase (SAK) is a therapeutic protein with promise for thrombolytic therapy of acute myocardial infarction. In this study, polyethylene glycol (PEG) aldehyde was used for N-terminal PEGylation of SAK to improve the pharmacological profiles of SAK. Due to the presence of the competitive PEGylation between the N terminus and the Lys residues, kinetic and stoichiometric analysis was carried out to investigate the process for the N-terminal PEGylation of SAK. To achieve this objective, size exclusion chromatography and tryptic peptide mapping were used to measure the PEGylation extent of SAK molecule and its specific amino acid residues, respectively.
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Investigation on PEGylation strategy of recombinant human interleukin-1 receptor antagonist.
Bioorganic & medicinal chemistry, 2007Co-Authors: Chunyang Zheng, Yongdong Liu, Guifeng Zhang, Jing Chen, Xiaoyan Suo, Guicai ZhangAbstract:Although PEGylation is a potential approach to prolong the half-lives and reduce the dosing frequency of therapeutic proteins, conjugation behaviors of polymer have pivotal effects on the remaining bioactivities of the derivatives. In this study, the PEGylation strategy of recombinant human interleukin-1 receptor antagonist was investigated. The random conjugation of polyethylene glycol to amino groups on the protein resulted in a severe loss of activity and only retained 9.8% of the activity. In contrast, the PEGylation at the thiol groups had moderate effects on the bioactivity of protein and 40% of activity was conserved. The results suggested that the thiol-target PEGylation was more beneficial for IL-1ra. (c) 2007 Elsevier Ltd. All rights reserved.
Ichiro Yamashita - One of the best experts on this subject based on the ideXlab platform.
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Solid-phase PEGylation of an immobilized protein cage on polyelectrolyte multilayer.
Colloids and surfaces. B Biointerfaces, 2013Co-Authors: Koichiro Uto, Kazuya Yamamoto, Kenji Iwahori, Takao Aoyagi, Ichiro YamashitaAbstract:We used a quartz crystal microbalance (QCM) to quantitatively characterize solid-phase poly(ethylene glycol) modification (PEGylation) of apoferritin that was electrostatically immobilized on the surface of a polyelectrolyte multilayer. The solid-phase PEGylation processes were monitored by analyzing QCM frequency shifts, which showed that the PEG chains were covalently introduced onto the surface of the immobilized apoferritin. We investigated the effect of PEG concentration, PEG molecular weight, and two-dimensional coverage of the immobilized apoferritin on the solid-phase PEGylation process in addition to the surface properties of the PEGylated apoferritin film, such as wettability and protein adsorption capacity. Since the reaction field is more spatially restricted in solid-phase PEGylation than in traditional aqueous-phase PEGylation, this study shows that a ferritin protein cage is potentially useful as a tailored building block, one that has well-defined structures different from the PEGylated ferritin prepared by an aqueous-phase approach.
