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Custom peptide synthesis

Leveraging our longstanding expertise of almost 50 years in peptide synthesis, we are pleased to support and accelerate your research by providing high-quality custom peptides from our UK-based and ISO 9001 certified laboratory. Our experienced chemists will work with you to create bespoke solutions specifically for all your peptide synthesis projects and synthesise custom peptides with a flexible range of scales (from 1 mg to multi-gram amounts) and purities to match your specifications. We work within industry-leading turnaround times and are able to provide the following peptide synthesis services to customers worldwide:

  •       Linear peptides from trimers up to peptides lengths of >99 amino acids (sequence dependent) of various complexity;
  •       Custom peptides with a diverse spectrum of modifications and post-translational modifications (e.g., incorporation of D-amino acids, unnatural amino acids, phosphorylated peptides, amino acid analogues, spacers, dyes);
  •       Structurally constrained peptides (e.g., head to tail cyclisation, disulfide bridged peptides, stapled peptides);
  •       Peptide antigens for antibody generation (e.g., MAPs peptides with reusable affinity columns suitable for serum purification, BSA or KLH conjugated peptides);
  •       DNA oligo-peptide conjugates;
  •       Peptides with fluorescent tags incorporated at both C and N termini;
  •       Peptide libraries and microarrays – Useful to generate overlapping peptides for screening large proteins and for epitope studies. We can also provide microarrays with individual peptides immobilised on a microscope slide.

Peptide synthesis with AltaBioscience

Quality and customer satisfaction focused, we deliver custom peptides according to stringent analytical specifications, with the purified peptides undergoing QC with HPLC and mass spectrometry.

We also offer additional options for peptide identification using amino acid analysis which will provide net peptide content and N-terminal protein sequencing providing the order of the amino acids in the peptide sequence.

Our highly skilled specialists will be able to offer you professional advice throughout the design and synthesis of the peptide sequence.

Frequently asked questions

How long does peptide synthesis take?

What purity is required for custom peptides?

Peptide solubility: How do I dissolve my peptide?

How to measure the concentration of a peptide solution?

What are peptides?

Like proteins, peptides are comprised of short chains of amino acids which are linked together by an amide or peptide bonds. Peptides and proteins mostly differ by their size, with peptides being short fragments of proteins, usually containing less than 50-100 amino acids.  Because of their smaller sizes, peptides have simpler structures and may not be able to fold and adopt secondary to quaternary structures like proteins. Nevertheless, small peptides are found in the body and also play important biological roles as they may for instance interact with receptors on an enzyme or cell causing biological events. The development of very efficient and specific peptide synthesis methods has enabled their routine usage as powerful research tools in biology. Custom peptides can be synthesised with the standard 20 natural amino acids, but also with unnatural amino acids such as D-amino acids or modified amino acids that confer them other specific structural and physicochemical properties than their natural counterparts.

To discuss the incorporation of non-standard amino acids in your peptide synthesis project, please contact our experts or download our technical document for further information.

Peptide applications

Peptides are used in a variety of applications and have distinct advantages over proteins in that they can be easily defined and synthesised quickly with consistency. Peptides used as therapeutics is a fast-growing area with increased number of peptides being used in drug therapies, vaccines and cosmetics. Coupled to DNA, peptide cargo can be transported easily into cells (DNA-peptide conjugates).

The high flexibility and well-established methods for peptide synthesis allows to produce carefully designed custom peptides that can for used for:

  • The generation of polyclonal and monoclonal antibodies when used as peptide antigens;
  • Determining the specificity of an antibody in competitive binding assays;
  • The contract manufacture of LFD devices;
  • ELISA assays as positive controls and enzyme immunological assays in inhibition and interaction studies;
  • Epitope studies when screening proteins;
  • Drug discovery;
  • Biological structure and function when used as probes;
  • Interaction studies e.g. protein-protein or ligand-receptor;
  • NMR studies;
  • Drugs in clinical trials;
  • The targeted delivery of drugs when used as drug delivery systems.

An introduction to peptide synthesis

Solid-Phase Peptide Synthesis (SPPS), developed in the late 1950s by Robert Bruce Merrifield, uses well-established Fmoc/tBu chemistry to anchor successive amino acids onto a growing chain immobilised on a polymeric support. It is a two-step cyclical process where the Fmoc protecting group from the amino acid immobilised onto the resin is first cleaved to expose the amine group. The resulting exposed amine is then reacted with the carboxylic acid group of a Fmoc protected amino acid to form an amide bond (peptide bond) using coupling reagents or activators. The deprotection and coupling steps are then repeated until the chain is assembled. It should be noted that the amino acid building blocks often have side chain protection to ensure that reactions only occur between amino and carboxyl groups of the amino acids being coupled. However, they are removed in the final stage when the desired peptide is cleaved from the immobilised support (resin).

At AltaBioscience, we incorporate additional steps such as double coupling and capping steps to further improve the synthesis and reduce prospects of deletions or poor coupling. We also undertake some solution phase peptide synthesis for example when cyclising peptides or generating disulphide bridges using Cys residues.

Solid phase peptide synthesis diagram:

Solid phase peptide synthesis diagram

 

How long does peptide synthesis take?

Peptide synthesis turnaround is dependent on the number of peptides required, purification options as well as scale and complexity of each peptide.

AltaBioscience offers a fast turnaround for standard small-scale peptides with completion generally in 7 – 10 working days and we can synthesise up to 576 non-purified peptides per batch in 6 – 8 working days with our Episcan peptide synthesiser.

Large scale, complex, large numbers or highly purified peptides will extend the turnaround time. However, we appreciate that projects may run under high time constraints and are happy to discuss turnaround times and how best we can help you meet your deadlines.

Peptide solubility: How do I dissolve my peptide?

Peptide solubility as a guide is determined by the overall charge of the peptide and the environment it exists in. Changing the pH can help in solubilising some peptides.

Care is needed when selecting your solvent and consideration should be given to the assay you intend to use it in, for instance, TFA may be toxic to cells in higher concentrations. DMSO is best avoided for peptides containing Cysteine, methionine and tryptophan as it may cause oxidation. As a general rule, where possible use volatile solvents, which can be removed by freeze drying to recover the peptide for further studies.

AltaBioscience offer a solubility test service which will provide information on the solubility of your peptide in 3 solvents. Due to the requirement to use additional peptide, this service is suitable for individual purified peptide orders of greater than 10mg amounts. Read more on peptide solubility and storage.

What purity is required for custom peptides? 

At AltaBioscience, we provide various purity options ranging from crude-desalted to over 95% purity. Peptide synthesis may generate impurities alongside the desired peptide such as truncated sequences, deletion sequences, incomplete deprotected sequences, racemised peptides or compounds from side reactions such as aspartimide formation or cysteine oxidation.

When ordering custom peptides, it is important to check that the requested level of peptide purity will be suitable for the intended research applications. Crude peptides without any purification such as obtained from Episcan scale are suitable for screening studies where a large number of peptides are initially tested before undertaking further studies. Standard purification to 80%-95% is suitable for applications such as polyclonal antibody generation and in-vitro assays and peptide blocking studies whereas higher purity over 95% is usually required for NMR studies, X-ray crystallography, enzyme and structural studies.

Our peptide chemists will be able to provide guidance on suitable purity levels for your required application. To discuss, contact our experts or learn more about peptide purification and peptide analysis here.

How to measure the concentration of peptides and proteins?

Determining the concentration of peptides or proteins can be achieved by either measuring the UV absorbance at 280 nm, by reacting the proteins or peptides with dyes and/or metal ions in colorimetric assays (e.g., Bradford assay, Lowry assay, BSA assay) or by performing amino acid analysis, the latter being considered as the gold standard method.

Amino acid analysis is usually performed when the concentration cannot be determined by UV absorbance due to the lack of aromatic tryptophan and tyrosine residues in the proteins or peptides. Although amino acid analysis requires specialist equipment, it is a robust and highly sensitive method that quantifies the concentration each individual amino acid in a sample. The protein or peptide concentration is therefore obtained by summing up the concentrations of the single amino acids. Amino acid analysis has also many advantages over colorimetric assays that can suffer from interferences when high concentrations of detergents or chaotropic agents are used. In addition, the dyes/metal ions in colorimetric assays may preferentially react with certain amino acids whereas the amino acids react equally during the derivatisation step when performing amino acid analysis.

At AltaBioscience, we provide a comprehensive peptide analysis service and in addition to our peptide synthesis service, we also offer amino acid analysis for the absolute protein quantification of proteins and custom peptides. Our amino acid analysis service is accredited to ISO/IEC 17025:2017.

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