Custom Peptides

Our custom peptide synthesis scientists are ready to offer reliable, confidential and constructive advice and a comprehensive quotation for the synthesis of the peptides that you need. Isca Biochemicals routinely completes many peptide syntheses, including difficult peptides (>100 amino acids), peptides containing unusual modifications and peptides with multiple disulphide bridges, and we are always looking for the next challenge.

Isca Biochemical standard peptide purity is >95% for catalogue products but this level of purity is not always required for custom peptides, particularly when it impacts costs and synthesis times. Please let us know your purity specifications at the outset of a project to make sure we provide the most appropriate product for your requirements.

A typical custom synthesis peptide run will yield between 5 - 50mg of the peptide in question, depending upon the number of amino acids and complexity of the product. However we have capacity for larger scale synthesis and are always happy to discuss the provision of multi-gram quantities – please contact us for details.

Custom peptide modifications available

Standard peptides are routinely provided as free N-terminal amines and C-terminal acids, although N-terminal acetylation and C-terminal amidation can be offered at no extra cost. Other peptide modifications we offer include:

Acetylation and amidation
Alkyne peptides
Biotinylation (as an N-terminal or lysine modification)
Chromogenic and fluorogenic substrates
Conjugation to a range of carrier proteins such as BSA and KLA, suitable for antibody production
Dye labelled peptides
Novel FRET pairs
Peptide cyclisation, either as a cysteine to cysteine disulfide bridge or as head-to-tail or side chain bridge
D-Amino acids – these may be incorporated as individual residues or as complete D-peptides
Farnesylation of cysteine and sulfhydryl functionalities
Fluorescent labelling - employing a range of fluorescent reagents including fluoresceins, rhodamines, coumarins and more
Glycosylation of serine and threonine
Hydrocarbon stapled peptides
MAP multiple antigen peptides with a range of functionalities.
Methylation at the N-terminus or the mono- di- or tri-methylation of lysine side chains
Multiple disulfide bridge peptides
Myristoylation and addition of fatty acids of various chain length
PEGylation with a wide variety of polyethylene glycol adducts
Phosphorylation of peptides with tyrosine, threonine and serine residues
Stable isotope labelling of peptides with 13C and 15N cold labels (and other isotopes on request)
Sulfation of tyrosine or serine

Purification and quality control

Isca Biochemicals pay close attention to every step of the synthetic process involved. Use of the best possible techniques and highest quality reagents and solvents to synthesise custom peptides allows us to minimise side reactions and impurities from the start. This has great benefits when purifying the final peptide.  All peptides are purified by reversed phase high performance liquid chromatography (HPLC), ion exchange chromatography or gel filtration techniques, with the higher specification bioscience grade peptides (>95%) being subject to our most rigorous purification.  Peptides of lower specification are similarly purified to whatever purity is required. This may be more cost effective and rapid and so is preferred for some peptide applications.


Peptides purified by reversed phase HPLC or ion exchange chromatography have their purity given as the area under the curve of the major peak when analysed at a specific wavelength, usually 230nm.

Mass Analysis
Mass spectroscopy analysis is performed to in order to conform the identity of the final product. A copy of the mass analysis is supplied as part of the datasheet delivered with the peptide.

Net peptide content
The majority of peptides supplied by us are in freeze dried form and will contain counter ions and physically bound water as a result of cleavage from resin, hplc and drying. These counter ions have no effect on the biochemical properties of the peptide but do have the effect of reducing the mass of peptide present in a given sample, usually to >70%. This may be confirmed by further analysis.

Amino Acid Analysis
This technique can be provided as an additional service and can also be used to determine net peptide if required. Please discuss this option at the start of the project if amino acid analysis will be required.

Nitrogen microanalysis can be also be provided as an additional service, and can also be used to determine net peptide. Please discuss this option at the start of the project if microanalysis will be required.

Storage and stability
Peptides supplied by Isca Biochemicals should be stored at -20°C, in dark conditions and kept desiccated. Peptides stored in this way should be stable for at least 6 months after leaving our laboratories.

Please contact us with your requirements - we look forward to hearing from you

email: [email protected]

Telephone (+44) 1392 422205

or use the form below:

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