Solid-Phase Peptide Synthesis (SPPS) Technology

Solid-phase peptide synthesis (SPPS) has been the main driving tool for peptide synthesis. It greatly simplifies the synthesis of peptides because the product can be directly separated using simple filtration at each step without the need for a more cumbersome extraction process. CD Formulation uses advanced SPPS technology to facilitate the rapid and efficient synthesis of peptides for a variety of applications, including therapeutics, research, and diagnostics.

What is Solid-Phase Peptide Synthesis (SPPS) Technology?

SPPS is a peptide synthesis technique. It is characterized by its intricate process of assembling peptides piece by piece. Picture this: the C-terminus of a peptide becomes firmly tethered to an insoluble polymer, a steadfast anchor from which the peptide chain will spring forth. The subsequent steps involve a meticulous addition of protected amino acids-each a vital component of the peptide's unique sequence-executed in a cycle of precision and care. Each amino acid addition is called a cycle, which includes the cleavage of the N-α protecting group, washing, coupling of the protected amino acid, and a washing step.

Fig. 1 Schematic representation of a solid-phase peptide synthesis (SPPS) system. (Rivera-de-Torre E, et al., 2022)

Our Services Related to Solid-Phase Peptide Synthesis (SPPS)

SPPS is the chemistry of choice for generating peptides with a wide range of structural architectures, ranging from 5 to 150 amino acids in length. SPPS is also the best method for assembling peptides with non-native or modified residues.

At CD Formulation, we strictly adhere to the basic principles of peptide synthesis. The entire synthesis process involves the following key steps:

• Use of amino acids modified with protecting groups (at the termini and side chains).
• Selection of an effective terminal deprotection strategy.
• Activation of new amino acids or fragments.
• Coupling between new amino acids and growing chains, i.e., peptide chain extension.
• Cleaning of intermediates.
• Cleavage of solid supports and side chain protecting groups.

In SPPS, peptide chain extension is achieved in a stepwise manner (one amino acid at a time), by fragment condensation (coupling peptide fragments instead of single amino acids), or a combination of both. Due to the cyclic nature of SPPS, deprotection is performed multiple times during the synthesis.

Most Commonly Used Protecting Groups for SPPS

Fmoc Group

• The Fmoc group has the advantages of mild reaction conditions, high yields, and few side reactions.
• The group cleaves under moderately alkaline conditions but remains stable under acidic conditions. This allows the use of unstable weakly acidic protecting groups such as Boc and benzyl on the side chains of amino acid residues in the target peptide.
• Our team provides a mild deprotection protocol using the Fmoc method, which involves a base (usually piperidine in DMF) to remove the Fmoc group and expose the α-amino group so that it can react with incoming active amino acids.

Boc Group

• Compared with the Fmoc group, the Boc group often uses strong acids, such as hydrofluoric acid or trifluoroacetic acid, in the deprotection step, which may not be ideal for acid-sensitive groups that need to be kept in the synthesis.
• However, in some cases, it can be easier to protect amino acids with specific side chains, especially those fragile protecting groups that are not easily hydrolyzed under strong acidic conditions.
• In addition, for some amino acids that are not resistant to alkaline conditions, the Boc group provides an alternative.

Most Commonly Used Reaction Solvents for SPPS

Dimethylformamide (DMF)

DMF has good solubility, but it is easy to generate N-acylurea as a byproduct in high dielectric constant solvents (DMF, CH2CN, DMSO, H2O, etc.). Therefore, as long as the reactants can be dissolved, low dielectric constant solvents (CH2Cl2, CCl4, C6H6, etc.) should be selected as much as possible.

Dichloromethane (DCM)

DCM is the most commonly used solvent in solid phase synthesis. Compared with using DMF as the reaction solvent, DCM has a low racemization rate and a slow generation rate of N-acylurea.

Choosing The Right Solid Support for Your Solid-Phase Peptide Synthesis (SPPS)

The solid support of SPPS consists of a stable resin and a reversible linker. A suitable linker is the key factor for the smooth progress of SPPS. The ideal linker must have the following characteristics:

• Sufficient stability to ensure that it does not change under various reaction conditions.
• Facilitate the connection of amino acids to solid carriers.
• Enable smooth selective cleavage at the end of the synthesis without degrading the final product.

We offer the following commonly used connectors to support your custom peptide synthesis projects.

Advantages of Solid Phase Peptide Synthesis (SPPS)

SPPS is a scalable, practical, economical, convenient, and efficient method for peptide chemical synthesis. Compared with traditional solution phase strategies, SPPS has significant advantages:

• Since the new chain is anchored to a solid support, large excesses of reagents can be used to ensure that the new amino acid or fragment (a fragment consisting of several amino acids) is properly coupled to the growing peptide chain.
• Due to the stability of the solid carrier, intermediate purification can be quickly filtered and washed, thus greatly simplifying the purification process.
• Since all steps of SPPS can be performed in a single reactor (one-pot synthesis), there is no need to transfer materials, thus simplifying and accelerating multi-step synthesis and avoiding losses caused by manual operations and repeated material transfers.
• The flexibility of solid supports makes solid-phase synthesis suitable for automation, making it ideal for industrial-scale production of peptides.

Custom Solid-Phase Peptide Synthesis (SPPS) Services

Deliverables

CD Formulation's peptides are delivered as lyophilized powders and packaged in separate sample tubes according to customer requirements. To ensure the quality of the peptides, we also provide the following documents for your reference:

• HPLC/MS Test: All peptides we produce are tested by MS and HPLC to ensure the accuracy of the peptide products.
• COA Document: We provide a COA document for each peptide, including the shape and appearance of the peptide sample, delivery specifications, molecular weight, and purity.
• Solubility Test: This is optional. We provide two solubility testing services according to customer requirements: qualitative dissolution test and quantitative dissolution test.

Publication

CD Formulation is designed to provide powerful tools for handling the synthesis of peptides of varying lengths and complexities. Please feel free to contact us if you are interested in our services. Learn how our SPPS technology can support your custom peptide synthesis projects.

How It Works

STEP 1

Submit a service request describing your specific research or development need.

STEP 2

We'll email you to provide your quote and confirm order details if applicable.

STEP 3

Execute the project with real-time communication, and deliver the final report promptly.