Custom Peptide Synthesis Service, high purity with fast delivery at low cost.

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Custom peptide synthesis service with fast delivery at low cost.

For a confidential quotation please use “Request a Quote” above.

Our standard peptide synthesis is designed for a peptide with a sequence of average difficulty:

  • Custom peptide synthesis from 2 to 120 amino acids
  • Scales from 1 mg to multi grams research grade production
  • Purities from crude to >98%


  • Crude Desalted – use for screening
  • >75% – immuno grade peptides: Polyclonal antibodies production, Antibody titering in ELISA
  • >85% – Biochemistry grade peptide: Western blotting studies, Non-quantitative enzyme substrate studies, Antibody affinity purification.
  • >95% – High purity peptide: Monoclonal antibodies production, Enzyme substrate studies, Receptor-ligand interaction studies, blocking and competition assays, ELISA and RIA, In vivo/vitro studies
  • >98%: NMR studies, Crystallography studies, Peptide references
  • Characterization by Mass Spectrometry
  • Purity by HPLC, Amino Acid Analysis, Sequencing, and Net Peptide Content available upon request
  • Peptide Quality Guarantee
  • Fast, on-time delivery, 1-2 weeks
  • Stapled peptides
  • Peptide arrays
  • Cosmetic peptide synthesis

Site Specific and Structure Modifications:

  • Cyclic peptides
  • Phosphorylated peptides
  • Conjugation to KLH, BSA, ETC
  • Biotinylation
  • Fluorescent lebelling
  • glycosylation, PEGylation, rhodamine, AMC, biotin, boronic amino acids, d-amino acids, stable isotopes, EDANS, dabsyl, dansyl, Abz, thiolactic acids, acetylation, sulphonation, matrix immobilization, alkylation, fatty acid attachment, succinylation, amidation, myristylation and many others
  • Incorporation of unusual amino acids including the following but please ask for your specific amino acid
    Majority of D-amino acids, D-Orn, Orn, Abu, Aib, (D)1-Nal, (D)2-Pal, (D)4-Cl-Phe, Nva, Nle, Hse, Hcy, Pen, Mpa, N-Methyl amino acid (Ala, Phe, Leu, Ile, Val, Gly, Met), b b-Ala, pGlu, Hyp, Dinitrobenzoylation (Lys), Lys(Me2), Phosphorylation (Tyr, Ser, Thr, single site), Tyr (SO3H2)

We routinely perform difficult synthesis such as synthesis of long peptides (>136 mers), peptides containing unusual modifications, cyclic peptides, cosmetic peptides and peptide oligonucleotide conjugates.
Our facility is equipped with state-of-the-art peptide synthesizers and, coupled with our experienced peptide chemists, we are able to deliver your custom peptide synthesis products quickly: our turnaround for custom peptide production is rapid. Most custom peptide orders are shipped within 1 to 2 weeks! and with high quality (purity of 90-95% is typical).

Each custom peptide synthesis project is carefully analyzed and analytical data are carefully examined by our chemists. Final synthetic peptide products are shipped with detailed quality control documentation including an HPLC trace, Mass Spec, and a Certificate of Analysis.
Additional analytical data (e.g., sequencing, amino acid analysis) are available upon request.

As a leading peptide manufacturer we deliver the lowest per peptide price for quality peptides.

Each custom peptide synthesis project is carefully analyzed and analytical data are carefully examined by our chemists. Final synthetic peptide products are shipped with detailed quality control documentation including an HPLC trace, Mass Spec, and a Certificate of Analysis.
Additional analytical data (e.g., sequencing, amino acid analysis) are available upon request.

Peptide design

There are a number of elements to consider when designing individual peptides, specifically amino acid composition, length, solubility and the application in which the peptides are to be used. For example, peptides of 10-15 residues are recommended for generation of peptide-antisera.

The amino acid content strongly influences the purification of the peptides and its solubility. The ratio of charged amino acids to uncharged ones and the number of hydrophobic residues are critical in determining the ease of solubility of a peptide.
It is recommended to have at least 20% charged residues to aid solubilisation.
A high content of hydrophobic residues will reduce the solubility of a peptide in aqueous solution.

If multiple Cysteine residues are present, disulfite links may form in the presence of oxygen. To minimize this, use a buffer containing reducing agent like 1,2-ethanediol (EDT) or dithiothreitol (DTT) or replace a Cysteine residue by a Serine one.

Usually purified by reverse phase HPLC with acetonitrile gradient and trifluoroacetic acid as moderator. A wavelength of 210-220 nm is used as this is the absorption wavelength of the peptide bond. It will remove all side-products and reagents used in the cleavage process and shorter peptides in some cases.


Though the TFA salt cannot be considered as an impurity it is very often suspected of having cell toxicity. In order to avoid this problem, an ion exchange to acetate or to hydrochloride may be required. This ion exchange requirement should be requested with the order.

Standard Peptide analysis

HPLC: Analytical High Performance Liquid Chromatography gives the purity level.
Mass Spectrometry:  gives the mass and proves the integrity of the peptide and gives the mass of the impurities. This analysis is performed by electrospray  ionization or MALDI-TOF.

Net Peptide Content
As peptides are isolated and provided as a lyophilized salt, they contain both counter-ions and residual water. The Net Peptide Content (NPC) is the percentage of total peptide relative to counter-ions and residual water.

The NPC is generally determined by quantitative amino acid analysis. The amount of each amino acid is measured after total acid hydrolysis. It is important that NPC and purity are taken into consideration to enable quantitative comparison of biological activity.

Peptides for Antisera Production
Production of anti-peptide antisera requires immunization of the host with the peptide conjugated to a carrier  protein in order to elicit a strong immune response.

Protein Carrier Conjugation

Activotec offers conjugation of peptides to a variety of immunogenic carrier proteins and gel for use as immunogen or for affinity purification. A variety of immunogenic carrier proteins such as Keyhole Limpet Hemocyanin (KLH), Diphtheria toxoid has been use in conjugation with several conjugation chemistries. KLH is often used since there is no cross-reactivity with reagents used in subsequent ELISA or Western blot experiments. We also offer coupling of peptide to various types of gel to create an immunosorbent, for positive or negative selection of macromolecular binding entries, such as antibodies.

If the peptide originates from the N-terminal region of the protein sequence, coupling to the carrier protein should be at the C-terminus of the peptide. And vice-versa.

For peptide without a free Cysteine in their sequence, a cysteine residue is added to the C- or the N-terminus to enable conjugation. N-terminus addition is recommended as it is less expensive to produce the free peptide for binding assays and the Cys-derivative for conjugation in the same synthesis.

The conjugation could be done with the C-terminal free carboxyl group or with the carboxyl group of Asp or Glu. This method is not recommended if there are Asp or Glu residues internally in the sequence.

Service Features:
Keyhole Limpet Hemocyanin (KLH), Bovine Serum Albumin (BSA), Rabbit Serum Albumin (RSA), Ovalbumin (OVA), Thyroglobulin, or Human Gamma Globulin (HGG). Other proteins are available upon request.
MBS (and other bi-functional linkers), which couple through sulfhydryl groups, and glutaraldehyde, which couples primarily through alpha, sigma & epsilon amino groups.

Serum production packages also available with large selection of host animals.

Custom Heavy Isotope Labelling


Custom Fluorescent Labelled Peptides
We offer a wide variety of fluorescent labelling services, which include expert technical advice on the selection of correct fluorescent labels for your applications. In addition to our usual quality control data sheet, we also include excitation and emission spectra for each product. While radio labelled peptides require special handling procedures and are expensive, our extensive range of fluorescent labelled peptides can be readily introduced during chain assembly or post-synthetically in a cost effective manner. We have the capability to construct any viable fluorescent peptide at your request.

Amine Reactive Labelling provides a wide variety of fluorescent labelled peptides. The vast majority of labels are designed for amino acid labelling, therefore, peptides can be labelled with an N-terminal free amine, internal sequence via amino acid side chain such as Lysine or Dap, or at the C-terminus of the peptide through the side chain of a lysine residue. Use the wavelength spectrum below to locate the label requirements for your research.

Fluorescent Resonance Energy Transfer (FRET) has been widely used in various biological applications. Peptide probes incorporating fluorescent donor/non-fluorescent acceptor combinations have been developed primarily for various detection of proteolysis and nucleic acid hybridization1,2 , receptor/ligand interactions3, distribution and transport of lipids4,5, membrane potential sensing6,7,8, cyclic AMP detection 9-14. Activotec has a range of fluorescent labels suitable for use in FRET peptides.

Red Labels
5-carboxytetramethylrhodamine [5TMR]
5.6-carboxytetramethylrhodamine [5(6)TMR]
6-carboxytetramethylrhodamine [6TMR]
Lissamine Rhodamine B [LRhodB]

Green Labels
5-carboxyfluoresceine [5FAM]
5,6-carboxyfluoresceine [5(6)FAM]
6-carboxyfluoresceine [6-FAM]
Methoxy coumarin acetic acid
Other Fluorescence Labeled Peptide probes also available such as
FITC/5-FAM (N-Terminal, Y/N Ahx)
MCA (N-Terminal)
HYNIC (N-Terminal)
DTPA (N-Terminal
Texas Red
and many others…

All custom labelled peptides include:
HPLC Analysis
MALDI-TOP Mass Spectrometry
Certificate of Analyses
Optional services: Amino acid Analysis and Sequencing

Custom Bioconjugation
Our services provide personalized solutions designed to supply researchers with the widest choice of tools to support their studies. As a recognized leader in providing bioconjugation services, Activotec custom product offerings include the modification of biopolymers or other biopolymers covalently linked through chemical or biochemical methods. Molecules we work with include nucleic acids and their analogs, peptides and their mimetics, proteins, antibodies and their fragments, enzymes, quenchers or fluorophores, avidin/streptavidin, solid support and other biologically active molecules. These bioconjugates are delivered by scientists with deep expertise in synthesis and bioconjugation chemistries and biology with a special focus on synthetic organic chemistry and biochemistry.
Biomolecule-small molecule labelling
Biomolecule-biomolecule conjugation
Immobilization on solid supports

Our bioconjugation service area includes:

  • Nucleic acid and oligonucletoide modifications, bio-labelling, conjugations
  • Antibody modifications and conjugations
  • Enzyme modifications and conjugations
  • Modifications with synthetic polymers and biopolymer conjugations
  • Avidin-Biotin System
  • Preparation of liposome conjugations
  • Macrosphere, Nano particle (gold-labelled) and any surface immobilization

Our Capabilities
We are not only capable of synthesizing synthetic molecules but also able to provide various bioconjugation systems for specific intended applications. Whether it is for tagging proteins to make them chromogenic or fluorescent, labelling molecules with biospecific ligands for subsequent affinity interactions, or cross linking two or more substances to create uniquely active conjugates, the choices are available in our laboratory. Our chemist will examine each project carefully, and customize a conjugation procedure on the basis of their chemical reactivities and other chemical properties that affect their behaviour during the conjugation process. This results in products that meet the specifications of the client.

Our investment in state-of-the-art analytical equipment provides industry-leading tools to develop and monitor our process. Complementary techniques, such as analytical chromatography and electrophoresis, are routinely used to verify that specifications are met. Sometimes, if the biopolymer is not too massive, Mass Spectroscopy can be used to determine its molecular weight. However, unless a crystal structure is available or a single unique functional group was used for conjugation, it may be difficult to know the exact conjugation site and the molar ratio of the reactants. Because of this complexity and difficulty, the effort required assessing the composition and purity of a bioconjugate depends largely on the requirements and rigor of the downstream research.

For a confidential quotation please use “Request a Quote” above.

For more detailed information: Tel: +44 (0)1223 260008 e-mail:

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