Peptide Synthesis

For peptide synthesis, we require the following information:

Sequence

The amino acid sequence from the amino terminus to the carboxyl terminus

Amino terminus

Typically, we provide peptide with a free amino terminus, but we can leave an easily reversible blocking group or add an essentially irreversible blocking group. It is also possible to purchase amino acids with modified amino termini (formyl methionine, for instance) for incorporation at the amino terminus of the peptide. In addition, we (or you) can perform chemistry on a free amino terminus to attach a reporter molecule such as biotin or a fluorochrome.

Carboxyl Terminus

We can arrange for the carboxyl terminus to be either a free carboxylic acid or an amide. There is a debate in the literature regarding whether peptides used for immunization should have acid or amide COOH termini.

Unusual amino acids

We can incorporate any commercially available amino acid or derivative so long as we can purchase the FMOC form. There are at least a full set of D amino acids and we can help you find more exotic compounds.

Cysteine

There are two main forms of cysteine available. One form (trityl) will give rise to a free SH group as a result of removing the peptide from the resin and side chain protecting groups from the peptide. That cysteine will be available for disulfide formation and other chemistries which depend on the free SH. The other cysteine derivative (Acm) will continue to have its sulfur group protected even after cleavage and deprotection of the rest of the peptide. This form of cysteine will not participate in disulfide formation, although it is still possible to remove the Acm group at a later time. If one does not plan to form disulfide bonds, we frequently will simply replace cysteine with either serine or alanine. These amino acids are much more 'natural' than a cysteine with a bulky (MW = 71) Acm group attached.

Quantity

Our most convenient synthesis scale on the multiple peptide synthesizer will provide between 5 and 25 milligrams of HPLC purified peptide. We can scale up a bit upon request and we can double or triple that amount by synthesizing your peptide in two or three batches. More than that will almost certainly be synthesized in one of our larger scale instruments.

Length

Currently, we consider up to 25 residues to be a pretty standard synthesis. For many purposes, even this is considered to be a large peptide. We have made peptides substantially longer than that (67 amino acids is our current record). Some long peptides turn out to be easy to synthesize and some short ones are nightmares. If you are designing peptides for the first time, please contact us so we can talk about your specific needs.

Cost

The current charge for 10 - 25 milligrams of peptide from the multiple peptide synthesizer for UNC system investigators is $225.00 each for anything up to a 12mer. This includes lyophilization following HPLC purification (>80%), a quantitative analytical HPLC trace, and mass spectrometer (time-of-flight, mass only) analysis of the purified product. For peptides longer than 12 amino acids, there is an additional charge of $15.00 per amino acid for the next 10 amino acids. For peptides larger than 22 amino acids, there is a minimum charge of $400.00 with a charge of $35.00 per additional amino acid. If you require a peptide larger than 32 residues, please contact us.

Synthesis rates for non-UNC groups are slightly higher - please contact us for those rates.

A complete Table of special charges for special services is available from our Facility upon request. These special services include chemistries such as biotinylation, incorporation of phosphorylated residues, incorporation of fluorescein or rhodamine, DNP labeling, conjugation of peptide to carrier protein, etc.

We have recently begun to offer a peptide-on-resin service for use as an affinity material for antibody isolation from immune serum. The charge for that is cost of peptide plus $100.00.

Alternatives

Peptide synthesis instruments operating at larger scales are available in the Facility and provide quantities of peptides ranging up to 150 milligrams. The minimum charge for UNC system investigators is a $225.00 set-up fee and $35.00 per amino acid. We suggest that you contact us regarding such syntheses. We can synthesize peptides at a much larger scale (gram quantities). Please contact us for a quotation if you need those kinds of quantities.

Time

The multiple peptide synthesizer is FAST - the actual synthesis, cleavage and deprotection of a typical peptide will be performed within 48-72 hours of receiving the order. Right now, HPLC purification takes at least a week due to the backlog of orders. Mass spectrometric analysis is performed within 24 hours. In the worst case, we should be able to deliver peptide in less than three weeks and it is typically faster than that for a standard peptide.

Ordering and Information

For more information and to place orders, call David Klapper at 966-5307 or FAX Dr. Klapper at 919 962-8103 or write to:

David Klapper
c/o Department of Microbiology and Immunology
Campus Box 7290
Chapel Hill, NC 27599
email: dgk501@med.unc.edu

An information form will be enclosed for ordering peptides in the future, and orders may also be placed though this web site (see above links).