Fundamentals of Modern Peptide Synthesis
Mesut Karahan in Synthetic Peptide Vaccine Models, 2021
Protein synthesis is important to study the structure of natural proteins, to investigate how protein structure and function are formed by the amino acid sequence and to understand the synthesis mechanism. However, it is not possible to form this structure by simply mixing the amino acids together. Protective groups are often necessary to avoid undesirable reactions. Chemical peptide synthesis generally starts from the carboxyl groups (C-terminus) of the peptide and proceeds towards the amino groups (N-terminus). This is the opposite direction of protein biosynthesis. The resulting bond is the amide (peptide) bond. It is necessary to use protective groups to control the C-N coupling reaction. Certain peptide bonds can be formed by protecting the amine group (N-terminus) of one amino acid and the carboxyl group (C-terminus) of the another. The protection of side chain functional groups is necessary to prevent undesirable reactions and to form univocally the goal peptide bond. The peptide bonds are also called eupeptide bonds to distinguish them from isopeptide bonds formed by participating side chain functional groups as is the case of glutathione for example. Peptide synthesis is a multistage process comprising a number of chemical processes. To provide an overall high yield of the goal peptide it is drastically important to have yields close to quantitative at all stages of this complex process. It is also extremely important to avoid even a low racemization at all stages otherwise the obtained peptide will lack the desirable physiological activity (Isidro-Llobet, Álvarez, and Albericio 2009).
Synthesis of Bioactive Peptides for Pharmaceutical Applications
Peter Grunwald in Pharmaceutical Biocatalysis, 2019
The common methods of peptide synthesis discussed in the previous sections are effective for enhanced peptide production. However, there exist challenges in the fabrication of certain sequences of peptides, mainly because of lesser rate of accomplishment with peptide complexity;improved chances of aggregation either inter- and/or intramolecular;inclined probability for the development of secondary structure and protecting groups that are hindered by steric arrangements which generate sequence for early termination. Thus, there are few novel or alternative techniques that have been developed in recent times as a solution to overcome these challenges.
Proteases as Biocatalysts for the Synthesis of Model Peptides
Willi Kullmann in Enzymatic Peptide Synthesis, 1987
Another technique for the preparation of peptides via protease catalysis was developed by Könnecke et al.44 after the model of liquid-phase peptide synthesis.45 Amino acids and dipeptides esterified to polyoxyethylene — a soluble polymeric support usually used in liquid-phase peptide syntheses — served as substrates during chymotryptic peptide bond formation. The coupling yields were rather moderate when Nα-protected amino acid or dipeptide polyoxyethylene esters were used as acyl group donors, while good yields were obtained with the amine components esterified to the soluble polymeric support. The novel approach to enzymatic peptide synthesis mainly profits from the solubilizing effects of the polyoxyethylene supports. As a result, the solubility of hydrophobic substrates in aqueous reaction media is increased without resorting to the solubilizing power of organic co-solvents (see above).
A non-functional neoepitope specific CD8+ T-cell response induced by tumor derived antigen exposure in vivo
Published in OncoImmunology, 2019
Mathias Vormehr, Katharina Reinhard, Renata Blatnik, Kathrin Josef, Jan David Beck, Nadja Salomon, Martin Suchan, Abderraouf Selmi, Fulvia Vascotto, Johannes Zerweck, Holger Wenschuh, Mustafa Diken, Sebastian Kreiter, Özlem Türeci, Angelika B. Riemer, Ugur Sahin
Peptide synthesis was performed by JPT Peptide Technologies GmbH via fully automated SPOT-synthesis approach (PepTrack™ Fast Track specification). A cellulose membrane was functionalized with the individual C-terminal amino acid for each peptide. After Fmoc- deprotection and washing, the activated amino acids were spotted to the membrane in a computer controlled and spatially addressed fashion. Deprotection, washing and amino acid coupling cycles were repeated until the complete peptide sequences were assembled. Following side-chain deprotection peptides were individually cleaved into microtiter-plate wells, analyzed by high-throughput HPLC-MS and dried. Finally, peptides were pooled and aliquoted in antigen representing matrix pools using an automated liquid handling system. RNAs were synthesized by BioNTech RNA Pharmaceuticals GmbH.12 Smc3 RNA encodes 27 amino acids with the mutated amino acid in the center (position 14). PME1 RNA represents five neoepitopes, CT26-ME1 to CT26-ME5 (27 amino acids per epitope) as described earlier.12 gp70 RNA codes for the H-2Ld-restricted epitope AH1423-431 derived from the murine leukemia virus envelope glycoprotein 70 (gp70) with single amino acid substitution at position five (V427A).18 All epitope sequences were embedded in a backbone described by Kreiter and colleagues.24
Polyaminoacid-based nanocarriers: a review of the latest candidates for oral drug delivery
Published in Expert Opinion on Drug Delivery, 2020
Sandra Robla, Maria José Alonso, Noemi S. Csaba
Among the synthesis strategies, solid-phase peptide synthesis (SPPS) is the most common technique for the synthesis of short peptides with controlled composition and length [25]. This method is based on the anchoring of an amino acid to a solid matrix and the subsequent addition of successive amino acids that bind to the initial unit, producing a lengthening polyaminoacid or peptide chain [26]. Another synthesis method uses reactive derivatives of amino acids (NCAs: amino acid N-carboxyanhydrides), where polypeptides or polypeptide-based synthesis are initiated by primary amines or alkoxide anions [27]. N-carboxyanhydride ring-opening polymerization (NCA-ROP) has permitted the production of high molecular weight homopolyaminoacids, as well as their functionalization with high reproducibility and minimal side product formation. Native chemical ligation (NCL) is based on a reaction between an unprotected peptide-thioester with another unprotected peptide containing an N-terminal cysteine in aqueous solution, producing a peptidic bond between the terminal cysteine of one peptide with the other [28]. Another method for synthesizing polypeptides is based on the chemo-enzymatic polymerization of amino acid monomers by aminolytic reaction using proteases, providing a green and clean chemical reaction with high yield in aqueous medium and mild conditions [29].
SPA: a peptide antagonist that acts as a cell-penetrating peptide for drug delivery
Published in Drug Delivery, 2020
Jingjing Song, Sujie Huang, Zhengzheng Zhang, Bo Jia, Huan Xie, Ming Kai, Wei Zhang
All peptides were synthesized using standard Fmoc solid phase peptide synthesis strategy. The fluorescein moiety (FITC) was attached to the N-terminus via an aminohexanoic acid spacer by treating a resin-bound peptide (0.1 mmol) with FITC (0.1 mmol), and diisopropyl ethyl amine (0.5 mmol) in DMF for 12 h. Stearic acid was coupled as a Fmoc amino acid. SPA-camptothecin conjugate was synthesized as described previously (Henne et al., 2006). All crude peptides were purified by reversed phase high performance liquid chromatography (RP-HPLC) on a C18 column. Purity analysis was checked by analytical RP-HPLC (Waters), and the peptides were eluted using a liner gradient of 5–95% acetonitrile in 0.1% trifluoroacetic acid at a flow rate of 1 mL/min within 30 min on a C18 column (Waters XBridge Columns, 10 μM, 4.6*250 mm). The retention time of each peptide was determined when the peak was at its maximum height. Identities of the synthetic peptides were confirmed by ESI-MS. The sequences of all peptides and conjugates were shown in the Supplymentry Table S1. All peptides and conjugates were dissolved in dimethyl sulfoxide (DMSO) with a final concentration of 10 mM.
Related Knowledge Centers
- Amine
- Carboxylic Acid
- Organic Chemistry
- Peptide
- Peptide Bond
- Amino Acid
- N-Terminus
- Protein Biosynthesis
- Protein Production
- Tert-Butyloxycarbonyl Protecting Group