Optimized PEG-PS resin core.
PEG-PS resins are ideal for longer and more challenging peptides. The
PEG-PS technology incorporates the benefits of PEG into a PS core to
provide a balance between swelling and polarity. In addition, these hybrid
resins maintain the mechanical integrity of polystyrene with the reduced
aggregation effects of PEG. ProTide® PEG-PS resins are optimized to create
an environment perfect for synthesizing long or difficult peptides. Hyper acid sensitivity is available via the chlorinated resins 2-chlorotrityl and Cl-TCP(Cl). When hyper acid sensitivity is needed at elevated temperatures, the Cl-TCP(Cl) resin is advantageous for its superior performance compared to the 2-chlorotrityl resin.
Another important factor is the peptide resin linker chosen for the reaction. The peptide linker is an integral part of the SPPS resin and serves as the connection point for the first amino acid in the sequence; upon peptide cleavage, linkers typically furnish C-terminal acids or amides. One commonly used peptide linker is the Wang linker, which serves as a connection point for the carboxylic acid C-terminus of a peptide. Also of note are peptide linkers that initially connect via the amine group, like the Rink linker, which connects the first amino acid through an amide at the C-terminus. For C-terminal peptide acids, the first amino acid coupling is problematic and prone to epimerization, so some resins are preloaded with the first amino acid for convenience. Other acid resins feature prechlorinated loading sites for easy loading without the risk of side reactions. Further resin and linker selection can improve a synthesis, particularly in the case of a challenging peptide synthesis. Sterically bulky linkers like the Cl-TCP(Cl) or 2-chlorotrityl linker show suppression of side reactions like diketopiperazine and piperidinyl alanine formation.1 The completed peptide and side chain protecting groups can be cleaved from the resin using concentrated trifluoroacetic acid (TFA) for most peptide linkers. Hyperacid sensitive linkers such as Cl-TCP(Cl) or 2-chlorotrityl can be cleaved with dilute TFA (<1%) to furnish a free, solution phase peptide with side chain protection intact for convenient post-synthetic modifications.
- High crude purity
- Easy to handle during all phases of SPPS, including work-up and cleavage
- Universal linker technology
- Cost savings
- Wide loading range (0.15 - 0.80 mmol/g)
- High reproducibility for consistent results