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Custom Peptide Synthesis & Antibodies

Custom peptide synthesis services provided by AAPPTec are available in all scales, from milligram research scale to multi-kilogram production scale. AAPPTec provides single custom peptides, multiple peptides and custom peptide libraries  in a timely manner at competitive prices.


Custom Peptide Synthesis

Custom peptide synthesis is AAPPTec’s specialty.  AAPPTec’s experienced peptide chemists can quickly and efficiently prepare most peptide sequences.   

AAPPTec chemists have experience and expertise in preparing long peptides in high purity.  As an example, AAPPTec has synthesized and delivered 78 to 81 amino acid custom peptides at 95% purity.

During each custom peptide synthesis, AAPPTec chemists utilize UV monitoring and in-process tests such as the Kaiser test to assure that each synthesis step is complete before proceeding with the synthesis.   If necessary, double coupling protocols are used to assure complete coupling.  In addition, heating may be utilized to accelerate slow or difficult reactions.  By assuring complete coupling of each amino acid, AAPPTec chemists maximize overall yield, minimize impurities and reduce the amount of purification required for each custom peptide.

In custom peptides containing hydrophobic sequences where hydrogen bonding of the peptide backbone can result in slow or incomplete reactions, AAPPTec chemists may utilize hydrogen-bond disrupting elements such as pseudoprolines or Dmb-protected amino acids.  In some cases, Boc chemistry with in situ neutralization affords higher yields than Fmoc chemistry.

In custom peptide synthesis, AAPPTec chemists take steps to minimize racemization of the activated amino acid in coupling which leads to undesired diasteromeic peptides.  Racemization during activation is minimized by activating the amino acid residue at reduced temperature and adding HOBt which suppresses the rate of racemization.   Cysteine and histidine are especially prone to racemization with uronium activating reagents. When racemization of these residues is especially troublesome, AAPPTec chemists may use carbodiimide/HOBt activation which results in lower levels of racemization.

All custom peptide products are provided with a complete quality control package, including HPLC and Mass Spectral Analysis, to confirm the purity and identity of the peptide. From 2 amino acids to 85 amino acids, AAPPTec can prepare peptides in the scale and purity required. We comply with the most stringent quality control specifications for a reasonable price.

Custom Peptide Prices

Custom peptide prices are determined mainly by three factors: the amount of peptide, the length of the peptide sequence and the amount of purification required.   For standard peptides, the purification costs may be a significant part of the custom peptide price.  Thus crude peptides are relatively inexpensive, while 95% pure peptides have higher prices than 85% pure peptides.  AAPPTec minimizes custom peptide prices by utilizing peptide synthesis protocols that produce crude peptides with high purity, thus reducing the purification costs.

Peptide prices will depend on the purity and quantitity of peptide required.  Longer peptides may be more difficult to synthesize due to hydrogen bonding between peptide chains and other factors.   Peptides containing 30 amino acids or more and peptides with modifications require special quotations.

To minimize the cost of custom peptides, do not request peptide purity greater than is necessary for your application.  The table below lists recommended peptide purities for various applications.

AAPPTec Custom Peptide Purity Levels

Immunological Grade: suitable for forming polyclonal antibodies

80% or Greater: tissue culture; ligand for affinity purification; non-quantitative antibody blocking experiments

90% or Greater: in vivo studies; bioassays; markers for electrophoresis; monoclonal antibodies

95% or Greater: ELISA; RIA; enzyme substrate

98%: NMR; chromatography standards

Custom Peptide Quotations and Ordering

To request a quotation on custom peptide synthesis, use our on-line quote request form or email your peptide sequence, quantity and purity requirements to and put “Custom Peptide Synthesis” in the subject line. Your information will be held in strict confidence.

  • All peptides are TFA salt unless it is specified otherwise in the customer’s PO. All custom peptides are peptide salts.
  • All peptides are sold only for experimental research, not for use in humans.
  • Customer must verify the sequence in the sales order and their PO; AAPPTec is not responsible for mistakes in the sequence or any biological activity 
  • Custom peptides can not be returned.


Peptide Synthesis Services

Peptide synthesis services that AAPPTec provides include incorporation of non-standard amino acids, modifications at the N-terminal, C-terminal or side chains, and the formation of cyclic structures.  Non-standard amino acids can usually be incorporated into a peptide synthesis with little difficulty.  Highly expensive building block, such as isotope-labeled amino acids, are incorporated most efficiently and cost effectively near the N-terminal.  

N-Terminal Modifications

Modification of the N-terminal of a custom peptide is generally on of the easiest and least costly modifications.  The modification can be simply made while the peptide is side chain protected and attached to the resin.  Typical N-terminal modifications that AAPPTec peptide synthesis services provide include acylation and labeling with biotin or fluorescent tags.

C-Terminal Modifications 

C-terminal amidation is a common modification that AAPPTec provides at minimal cost.  Common amide resins such as Rink amide resin or Sieber amide resin are utilized in preparing these peptides.   Other modifications at the C-terminal are more difficult.  Special resins or a combination of solid and solution phase reactions are required; consequently C-terminal modifications often are more costly.

Side Chain Modification 

Peptides may be labeled on a lysine side chain with biotin or a fluorescent dye.   Side chain modifications such as acetylation, methylation or phosphorylation are often involved in regulatory processes.  Phosphorylation of serine, threonine or tyrosine residues; methylation of lysine or arginine residues, and acylation of lysine or serine residues are some of the side chain modifications that AAPPTec peptide synthesis services can incorporate.   Often the most efficient method of preparing side-chain modified peptide is to incorporate the amino acid residue with the appropriate side chain modification into the synthesis.  When this is not practical, an amino acid with a side chain protecting group that can be selectively removed is utilized.

Cyclic Peptides 

Cyclization is another common modification provided by AAPPTec custom peptide synthesis services.   The most common type of cyclization is formation of a Cys-Cys disulfide bond.   This cyclization can be performed relatively easily when there is only one disulfide bond to be formed.  Peptides containing multiple disulfide bonds are more difficult to prepare and require selective deprotection schemes and additional steps to assure the proper bond formations.  Consequentially these peptides are more costly to prepare.

Head to tail cyclization, in which the C-terminal is bonded to the N-terminal, is another common type of cyclization.  The success of this cyclization may depend on the sequence of the linear peptide precursor.  Similar cyclizations are bonds formed between residue sidechains and the N- or C-terminal of peptides.  Less often, cyclization is produced by forming amide or ester bonds between amino acid side chains.

Peptide stapling is a relatively new form of cyclization that is utilized to stabilize the helical structure of peptides.  The rings are usually formed by ring-closing metathesis of two alkenyl amino acid residues.   The helix-stabilizing rings may also be formed by click chemistry, but this methodology has not been as widely utilized.  

Additional Services

AAPPTec can provide the following services for an additional fee.

  • Amino Acid Analysis 
  • Aliquoting
  • TFA Removal

Large Scale Custom Peptide Production

AAPPTec can perform custom peptide synthesis in larger scales, from gram to multi-kilogram quantities. AAPPTec complies with the most stringent quality control specifications at a competitive price. Let our experienced chemists assist with your development and production needs. All requests are evaluated with strict confidentiality.

From our extensive experience in custom peptide synthesis, to our well-trained technical team and highest production standards, we hope to be your strong and reliable partner in the life sciences industry.

Custom Antibodies

AAPPTec provides complete custom antibody production service for our customers, including peptide design and synthesis, protein expression and purification, custom monoclonal antibody production, custom polyclonal antibody production, affinity purification, identification and labeling. We offer our antibody customers the expertise and dedication to quality that has made AAPPTec the leader in custom peptides.

AAPPTec offers a variety of monoclonal and polyclonal antibody production packages.  More about Custom Antibodies