ChemInform Abstract: N-ALKYLATION OF AMINO ACID RESIDUES BY CHLOROMETHYL GROUPS. A POTENTIAL SIDE REACTION IN THE SOLID PHASE PEPTIDE SYNTHESIS

1979 ◽  
Vol 10 (7) ◽  
Author(s):  
M. CHRISTENSEN ◽  
O. SCHOU
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Side Reaction ◽  
Amino Acid Residues

scholarly journals Microwave-assisted solid-phase peptide synthesis of neurosecretory protein GL composed of 80 amino acid residues

2015 ◽  
Vol 21 (6) ◽  
pp. 454-460 ◽  
Author(s):  
Keiko Masuda ◽  
Haruka Ooyama ◽  
Kenshiro Shikano ◽  
Kunihiro Kondo ◽  
Megumi Furumitsu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Amino Acid Residues ◽  
Microwave Assisted

scholarly journals Tea Bags for Fmoc Solid-Phase Peptide Synthesis: An Example of Circular Economy

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5035
Author(s):  
Fanny Guzmán ◽  
Adriana Gauna ◽  
Tanya Roman ◽  
Omar Luna ◽  
Claudio Álvarez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Circular Economy ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Wide Field ◽  
Amino Acid Residues ◽  
Recycling System ◽  
Physicochemical Features

Peptide synthesis is an area with a wide field of application, from biomedicine to nanotechnology, that offers the option of simultaneously synthesizing a large number of sequences for the purpose of preliminary screening, which is a powerful tool. Nevertheless, standard protocols generate large volumes of solvent waste. Here, we present a protocol for the multiple Fmoc solid-phase peptide synthesis in tea bags, where reagent recycling steps are included. Fifty-two peptides with wide amino acid composition and seven to twenty amino acid residues in length were synthesized in less than three weeks. A clustering analysis was performed, grouping the peptides by physicochemical features. Although a relationship between the overall yield and the physicochemical features of the sequences was not established, the process showed good performance despite sequence diversity. The recycling system allowed to reduce N, N-dimethylformamide usage by 25–30% and reduce the deprotection reagent usage by 50%. This protocol has been optimized for the simultaneous synthesis of a large number of peptide sequences. Additionally, a reagent recycling system was included in the procedure, which turns the process into a framework of circular economy, without affecting the quality of the products obtained.

A Strategy for Thioamide Incorporation During Fmoc Solid-Phase Peptide Synthesis with Robust Stereochemical Integrity

2019 ◽  
Author(s):  
luis camacho III ◽  
Bryan J. Lampkin ◽  
Brett VanVeller
Keyword(s):  
Amino Acid ◽  
Functional Groups ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Side Chains ◽  
Amino Acid Side Chains ◽  
Peptide Elongation

We describe a method to protect the sensitive stereochemistry of the thioamide—in analogy to the protection of the functional groups of amino acid side chains—in order to preserve the thioamide moiety during peptide elongation.<br>

Instrumentation for automated solid phase peptide synthesis

1999 ◽  
Author(s):  
Linda E. Cammish ◽  
Steven A. Kates
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Reaction Vessel ◽  
Automated System ◽  
Polymeric Support ◽  
Simple Filtration ◽  
Subsequent Activation ◽  
Selection Of

The concept of solid phase peptide synthesis introduced by Merrifield in 1963 involves elongating a peptide chain on a polymeric support via a two-step repetitive process: removal of the Nα-protecting group and coupling of the next incoming amino acid. A second feature of the solid phase technique is that reagents are added in large excesses which can be removed by simple filtration and washing. Since these operations occur in a single reaction vessel, the entire process is amenable to automation. Essential requirements for a fully automatic synthesizer include a set of solvent and reagent reservoirs, as well as a suitable reaction vessel to contain the solid support and enable mixing with solvents and reagents. Additionally, a system is required for selection of specific solvents and reagents with accurate measurement for delivery to and removal from the reaction vessel, and a programmer to facilitate these automatic operations is necessary. The current commercially available instruments offer a variety of features in terms of their scale (15 mg to 5 kg of resin), chemical compatibility with 9-fluorenylmethyloxycarbonyl/tert-butyl (Fmoc/tBu) and tert-butyloxycarbonyl/ benzyl (Boc/Bzl)-based methods, software (reaction monitoring and feedback control), and flexibility (additional washing and multiple activation strategies). In addition, certain instruments are better suited for the synthesis of more complex peptides such as cyclic, phosphorylated, and glycosylated sequences while others possess the ability to assemble a large number of peptide sequences. The selection of an instrument is dependent on the requirements and demands of an individual laboratory. This chapter will describe the features of the currently available systems. As the field of solid phase synthesis evolved, manufacturers designed systems based on the synergy between chemistry and engineering. A key component to an instrument is the handling of amino acids and their subsequent activation to couple to a polymeric support. The goal of an automated system is to duplicate conditions that provide stability to reactive species that might decompose. Standard protocols for automated synthesis incorporate carbodiimide, phosphonium, and aminium/uronium reagents, preformed active esters, and acid fluorides. For further details on coupling methods, see Chapter 3. A second issue related to coupling chemistry is the time required to dissolve an amino acid and store this solution.

Purification of large peptides using Chemoselective tags

1999 ◽  
Author(s):  
Paolo Mascagni
Keyword(s):  
Amino Acid ◽  
Synthetic Peptides ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Exchange Chromatography ◽  
Target Sequence ◽  
Coupling Reactions ◽  
Amino Acid Residues ◽  
Quaternary Structures ◽  
Specific Stationary Phase

In solid phase peptide synthesis (SPPS), deletion sequences are generated at each addition of amino acid due to non-quantitative coupling reactions. Their concentration increases exponentially with the length of the peptide chain, and after many cycles not only do they represent a large proportion of the crude preparation, but they can also exhibit physicochemical characteristics similar to the target sequence. Thus, these deletion-sequence contaminants present major problems for removal, or even detection. In general, purification of synthetic peptides by conventional chromatography is based on hydrophobicity differences (using RP-HPLC) and charge differences (using ion-exchange chromatography). For short sequences, the use of one or both techniques is in general sufficient to obtain a product with high purity. However, on increasing the number of amino acid residues, the peptide secondary and progressively tertiary and quaternary structures begin to play an important role and the conformation of the largest peptides can decisively affect their retention behaviour. Furthermore, very closely related impurities such as deletion sequences lacking one or few residues can be chromatographically indistinguishable from the target sequence. Therefore, purification of large synthetic peptides is a complex and time-consuming task that requires the use of several separation techniques with the inevitable dramatic reduction in yields of the final material. Permanent termination (capping) of unreacted chains using a large excess of an acylating agent after each coupling step prevents the formation of deletion sequences and generates N-truncated peptides. However, even under these more favourable conditions, separation of the target sequence from chromatographically similar N-capped polypeptides requires extensive purification. If the target sequence could be specifically and transiently labelled so that the resulting product were selectively recognized by a specific stationary phase, then separation from impurities should be facilitated. This chapter deals with such an approach and in particular with the purification of large polypeptides, assembled by solid phase strategy, using lipophilic and biotin-based 9-fluorenylmethoxycarbonyl (Fmoc) chromatographic probes. Assuming that the formation of deletion sequences is prevented by capping unreacted chains, a reciprocal strategy can be applied that involves functional protection of all polymer-supported peptide chains that are still growing, with a specially chosen affinity reagent or chromatographic probe.

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