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Offering services for: High quality synthetic peptides, stable isotope labeled peptides, peptides with PTM’s and fluorescent and affinity tags, synthesis of peptide libraries. Analysis of synthetic peptides. Purification, lyophilization and aliquoting of synthetic peptides

The core facility offers services for UNC and external users.

For more information or quotations please contact us at

Peptide Synthesis

Generally four levels of peptide purity are available, with each level of purity serving a different application:

  1. Crude peptides (without analytical data unless separately ordered)
  2. Desalted peptides (purity usually 50-70%, RP-HPLC profile and MS data will be provided)
  3. >80% HPLC-purified peptides (analytical RP-HPLC profile and MS data will be provided)
  4. >95% HPLC-purified peptides (analytical RP-HPLC profile and MS data will be provided).

All peptides after cleavage from resins are pre-purified by precipitation, washing with organic solvent and lyophilization. Both crude and purified peptides are delivered as lyophilized powders. The turn-around time generally is 1-2 weeks for crude peptides and 2-3 weeks for purified peptides. There are four synthesis scales to choose from: 10, 25, 50, and 100 µmol (if need large scale synthesis please contact us). For each of these scales, the peptide can be obtained either in crude, desalted, or purified form. MAPs are available in crude or desalted form.

Histone Peptides

We can provide histone peptide sequences in quantities starting from 100 µg, including sequences with PTMs, biotin, and/or with fluorescent tags (e.g. 5-Fam, 5-Tamra).

For examples of the peptides please check a link below.


Typical applications of synthetic peptides at various purity levels

Crude and “desalted” peptides are usually used for high-throughput screening (e.g. preliminary screening of large number of peptides for lead generation). Desalted peptides are preferred when salts can interfere with the assay or when good estimation of peptide concentration is needed.

  • >80% pure peptides are used as antigens for antibody production, purification, and blocking, as ligands for affinity purification, in enzyme substrate studies, epitope mapping, ELISA, and bioassays
  • >95% pure peptides are usually used in quantitative bioassays, as enzyme substrates/inhibitors in quantitative studies, markers for electrophoresis, chromatography standards, in NMR, ELISA, crystallization, ITC, and SAR studies

The ranges of expected yields for each scale and purity level are given in the table.

Synthesis Scale
Range of typical yields (mg)
(in µmol)
10 µmol
25 µmol
50 µmol
100 µmol


Peptide purityshould not be confused with peptide content. For example, 100% pure peptide, contains water (usually 3-10%) trifluoroacetate or acetate counterions, and may also contain residual TFA. Peptides are usually hygroscopic and water content increases during storage and handling.

Synthesis of Peptides Containing Modified Amino Acids

We can incorporate a wide range of modified amino acids into synthetic peptides. The primary limitation is the commercial availability of required Fmoc-amino acid derivatives. Since incorporation of modified amino acids often will increase the difficulty of peptide synthesis, this may lead to lower yields or purity of the product. In some instances the complications of incorporating the unusual amino acid can be minimized by its position in the peptide sequence. Usually preferred positions for modified residues are those close to N-terminus of the peptide sequence (especially for phospho-amino acid and trimethyl-lysine residues). The incorporation of modified amino acids in the peptide will also result in additional charges, usually the price of Fmoc derivative of the modified amino acid (please contact us for details).


Multiple Antigenic Peptides (MAPs) offer an alternative approach to for raising antibodies using synthetic peptides. Peptide epitopes attached to a 4 or 8 branching core (the core of 3 or 7 Lys residues) result in three dimensional molecules with highly localized epitope density and no additional peptide sequences. MAPs (molecular size between 5 and 15 kDa) are suitable for direct antibody production without the need to couple to a carrier protein. Multiple copies of antigen epitopes in MAPs have been shown to produce strong immunogenic response (see References 6 and 7).

Synthesis of Peptide Libraries

We can help in the design of a peptide library. We can synthesize the library of ≤120 crude peptides within 2-3 weeks, for larger libraries we need 2 additional weeks per 120 peptides. The peptides are delivered as lyophilized powders in separate vials or as lyophilized aliquots in eppendorf tubes (additional fee). The quality of 1/12 of library peptides is checked by MS and RP HPLC. We can check the quality of other library peptides at users request for additional fee (see price list).

Analysis of Synthetic Peptides

We can analyze user provided samples of crude or HPLC purified peptides using analytical HPLC and mass spectrometry.

Purification, Lyophilization, and Aliquoting

We can also purify crude peptides supplied by users using reverse phase preparative HPLC method. We will provide the purification profile data and analytical data for peptide after purification. The peptides will be lyophilized after purification and can be aliquoted on user request. We can precisely weight the lyophilized peptides using microbalance with anti-static device and prepare lyophilized aliquots in 1.5mL or 2mL eppendorf tubes using speed-vac (up to 40 tubes per run).

Guide to Peptide Storage and Handling

For a short period of time solid peptides can be stored at 4o C.
For a long term storage -20o C or -80o C is suggested, especially for peptides containing M, C, W residues and DD, DG, DS, NN, NG sequences.
Peptide solutions should be prepared just before experiments and, if needed, stored at -80o C.
The number of freezing / thawing cycles for these solutions should be reduced to minimum (after each cycle the solutions should be inspected for signs of precipitation).
Peptides containing M, C, W, and especially DG, DD, DN, NG, NN, ND sequences are not stable in solution. Stability of peptides containing M, C, or W residues may be improved by addition of reducing agents (e.g. DTT or BME).
If peptide solubility in water or water based buffers is low the peptide can be dissolved in solution containing organic solvent (e.g. acetonitrile, methanol, acetic acid, DMSO, DMF) and then diluted with water to desired concentrations.
Sometimes changing pH, e.g. by addition of diluted acetic acid, may be helpful.

Acknowledging the HTPSA Core Facility

Please acknowledge use of the HTPSA Core Facility in your presentations and publications. This will help us demonstrate the Core Facility’s value for the local scientific community. We obtain on-going support from the UNC Lineberger Comprehensive Cancer Center through the University Cancer Research Fund and the Cancer Center Support Grant. Consequently, publications supported by the UNC Center for Structural Biology must acknowledge NIH grant P30CA016086 and be submitted to PubMed Central in compliance with the NIH Public Access Policy.

Example of acknowledgment

Peptide synthesis was performed in the High-Throughput Peptide Synthesis and Arrays Core Facility at University of North Carolina in Chapel Hill. North Carolina Biotechnology Center Institutional Development Grant provided funding to develop this facility.