Customized Synthesized Peptide/Proteins

What is Peptide Synthesis?

Peptides are biologically active substances intimately related to various cellular functions within living organisms. Their molecular structure lies between that of amino acids and proteins, constituting compounds formed through the bonding of multiple amino acids in a specific sequential arrangement via peptide bonds. Peptides serve as a collective term for biologically active substances involved in various cellular functions and find extensive applications in functional analysis, antibody research, and notably, pharmaceutical research.

Peptide synthesis entails the process of pairing carboxyl groups (referred to as the C-terminus) and amino groups (referred to as the N-terminus). Due to the potential occurrence of unexpected reactions, protective groups become imperative. The chemical synthesis of peptides initiates from the C-terminus and concludes at the N-terminus, while protein biosynthesis follows the opposite direction, commencing at the N-terminus and terminating at the C-terminus.

Advanced Peptide Synthesis Platform

To cater to our clientele with dependable lead times, we boast a world-class, fully automated, multi-channel peptide synthesizer imported from leading global manufacturers. One of our synthesizers can simultaneously produce 96 different peptide sequences. We possess state-of-the-art peptide purification and detection equipment, a proficient team with extensive experience in peptide synthesis and chemical synthesis spanning several years, an advanced service infrastructure, a scale-up production capability, and a scientific management system. All these elements converge to offer high-quality services to research users worldwide. We can fulfill customer demands for milligrams to grams of peptide synthesis and purification services at competitive prices.

What Do We Offer?

General Linear Peptide Synthesis: We offer peptide synthesis services for linear peptides with chain lengths ranging up to 120 amino acids, from milligram to gram quantities, achieving purities of up to 99%. Shorter peptides are synthesized using solid-phase synthesis, while longer peptides are produced through recombinant expression.

Simple Modified Peptides: We provide N-terminal acetylation and C-terminal amidation services for basic peptide modifications.

Diverse Modified Peptides: Our capabilities extend to synthesizing various modified peptides, including phosphorylated peptides (Ser, Thr, Tyr), methylated peptides (lysine with one, two, or three methyl groups), acetylated peptides (lysine), and peptides modified with fatty acids (Palmitoyl, Myristoyl), among others.

Peptides Containing Unusual Amino Acids: We specialize in synthesizing peptides that contain D-amino acids and various amino acid derivatives to meet specific research requirements.

Varied Purity Levels: We accommodate different purity requirements, offering peptides with varying levels of purity, ranging from crude peptides to >75%, >85%, >90%, >95%, and >98% purity.

Peptide Conjugation to Carrier Proteins: We also offer services for cross-linking peptides to carrier proteins such as Keyhole Limpet Hemocyanin (KLH), Bovine Serum Albumin (BSA), Ovalbumin (OVA), and Thyroglobulin (TG), facilitating applications in immunogenicity studies and vaccine development.

The peptide synthesis service we offer includes:

Synthetic Methods Used In Creative Proteomics

Fmoc and Boc methodologies are both employed, using solid and solution phase reactions. Boc-chemistry solid phase peptide synthesis allows us to synthesise difficult sequences, and gives a greater flexibility in the synthesis of modified peptides. Fmoc chemistry is most suitable for simple peptides and sequences prone to oxidation.

Quality assurance files supplied after synthetic:

All peptides are supplied with COA, RP-HPLC and Mass Spec data. CHN analysis (available, will be online soon), amino acid analysis and N-terminal sequencing can be supplied at an extra cost. View example data: COA, RP-HPLC and Mass Spec.

About the purity

• The most common MS grade purity requested is >95%;
• Antibody production >85% purity is often sufficient;
• NMR and Crystallography >98% is recommended;
• Crude peptides (>50%) can be used for screening large numbers of peptides.
• Any other purity requirement, PLEASE FEEL FREE TO CONTACT US!

Custom Synthesis of Long and Complex Peptides

In the realm of chemical synthesis of long peptides, solid-phase synthesis stands as the most commonly employed and straightforward method. However, as the peptide chain extends, the reactions gradually become more challenging, giving rise to truncated or incomplete sequences in the desired peptide. Within the synthesis process of long peptides, the primary challenge lies in the exploration of superior reaction conditions and methodologies, thereby ensuring more thorough and complete amino acid condensation reactions.

Creative Proteomics' Research and Development division, building upon years of experimentation and exploration, has further perfected the techniques and methods for the synthesis of long and complex peptides. Currently, we have successfully synthesized peptides exceeding 150 amino acids in length.

Service Advantages

High Quality: We offer a comprehensive quality assurance package, including Certificate of Analysis (COA), Mass Spectrometry (MS) data, High-Performance Liquid Chromatography (HPLC) chromatograms, and detailed inspection reports. Moreover, we can provide peptide content analysis reports, amino acid analysis reports, endotoxin detection reports, and recommendations for peptide solubility, tailored to customer specifications.

Advanced Technology: Our company possesses expertise in both solid-phase and liquid-phase peptide synthesis technologies, enabling us to employ a combination of these techniques to overcome challenges associated with difficult and complex peptides.

Diverse Modification Capabilities: We offer a wide array of over 400 modifications, encompassing fluorescence labeling, various cyclization techniques, and more. Our success rate exceeds 99%.

Strict Confidentiality: We are committed to safeguarding sensitive information. Confidentiality agreements can be established to ensure the security of your research and proprietary data.

Isotope Dilution Strategy: Advancing Quantification in Mass Spectrometry-Based Research

Regarding its success in MS-based quantification of small molecules, the isotope dilution strategy has been recognized as the reference method for internal standardization, introduced into protein quantification with unique advantages over conventional ligand binding assay. In these approaches, the sample is spiked with defined amounts of stable isotope-labeled analogue(s) of unique peptides (AQUA strategy) or intact target protein(s) (PSAQ strategy), to establish the calibrating curves. The mass spec standards of high purity, no matter AQUA peptides or PSAQ proteins, Creative Proteomics can help to synthesize it, to promote your research.

If the target proteins are endogenous ones for the organism and it's not easy to obtain the blank matrix to prepare calibrating samples, only stable isotope labeled peptides or proteins, especially at the backbone of arginine and lysine, work well in the absolute quantitative proteomics. If the targeted proteins are exogenous for the organism, such as protein therapeutics, and collected blank matrix is available, naive peptides/proteins of high purity can be also used for reference standards without any isotope labeling. For both labeled and non-labeled forms, the experienced professionals can provide solid phase peptide synthesis service for peptides, and intact proteins by proper biosynthesis, folding and modifications with host cells. For SIL peptides/proteins, the products from Creative Proteomics are not only highly pure, but also synthesized with high isotope incorporation, for excellent MS analysis.

How To Place An Order

*If your organization requires signing of a confidentiality agreement, please contact us by email

What is the maximum length of peptides that can be synthesized?

We have successfully synthesized peptides with lengths of up to 120 amino acids. Peptides with lengths of 50 amino acids or fewer fall within the realm of routine synthesis.

How should peptides be handled and stored?

Peptides in lyophilized powder form can be stably transported at room temperature when sealed. Peptides in solution should not be stored for extended periods.

Peptide Storage Guidelines: Peptides intended for long-term storage should be kept in lyophilized powder form, sealed within containers containing desiccants, and stored at -20°C. Storage at -80°C is even more effective and can maximize peptide stability, preventing degradation caused by bacteria, oxidation, and secondary structure formation.

What does peptide purity refer to?

Peptide purity refers to the content of the target peptide detected at 214 nm by the High-Performance Liquid Chromatography (HPLC) method (214 nm being the absorption wavelength of peptide chains). It does not detect water or residual salts. Other impurities may include:

Missing Sequences (amino acid residues missing from the target sequence).

Truncated Sequences (sequences generated during the capping process).

Incompletely Deprotected Sequences (arising from the entire synthesis process or the final cleavage step).

Peptide purification does not involve water and salts. HPLC purification can introduce minor impurities such as trifluoroacetic acid (TFA), generated from free amino termini and side chains like Arg, Lys, and His. Typically, delivered peptides may contain trace amounts of TFA and residual water, even in lyophilized form, depending on their covalent binding capabilities.

What other substances (impurities) may be present in peptides?

Impurities present in pre-purified peptides include both peptide and non-peptide substances. Post-purification, impurities in peptides, apart from TFA salts, mainly consist of peptide sequences that have undergone modifications:

Missing sequences (amino acid residues missing from the target sequence).

Truncated sequences (generated during the capping process).

Arising from the entire synthesis process or the final cleavage step.

Protection groups reattaching at other locations on the peptide.

What is peptide net content?

Peptide net content differs from peptide purity. It refers to the amount of peptide relative to non-peptide substances (primarily counterions and water). It can be determined through amino acid analysis. Hydrophilic peptides may absorb trace amounts of water even in a rigorously lyophilized state. Different batches of peptides may have varying net contents due to purification and lyophilization processes.

How can synthesized peptides be quality-checked?

We maintain strict confidentiality for all materials provided by clients. We always provide HPLC and MS testing results when delivering products. All peptides are purified using reverse-phase chromatography. Mass spectrometry determines the molecular weight of the peptides to verify their correctness, with MS results revealing most major impurities. If necessary, peptide net content testing, such as amino acid analysis or elemental analysis, can be provided. These methods confirm the amino acid composition of peptides and serve as supplementary confirmation techniques. All delivered peptides meet the purity requirements specified by the client.

How should peptides be dissolved?

The solubility of peptides largely depends on their polarity. Acidic peptides dissolve in basic solutions, while basic peptides dissolve in acidic solutions. Hydrophobic or neutral peptides with a significant number of uncharged polar amino acid residues can be initially dissolved in small amounts of organic solvents such as DMSO, DMF, acetic acid, acetonitrile, methanol, ethanol, or isopropanol, followed by dilution with water (distilled water). Peptides containing methionine or cysteine should not be dissolved in DMSO as DMSO may cause side chain oxidation.

How do I choose the appropriate purity level for my research?

Crude peptides are not recommended for biological experiments. They may contain a substantial amount of non-peptide impurities, such as residual organic solvents, cleavage reagents, TFA, and other incomplete peptides. TFA cannot be completely eliminated, and peptides are typically delivered in the form of TFA salts. If residual TFA affects your experiments, we recommend alternative salt forms, such as acetate or hydrochloride salts, which are usually 20-30% more expensive than conventional TFA salts. This is due to more significant peptide loss and the need for additional raw materials during the conversion process.

What are protecting groups?

Protecting groups are segments that can bind to functional groups and block their reactivity. Some are acid-labile protecting groups, such as Boc and tert-butyl esters. Others are base-labile protecting groups, such as Fmoc and Fm esters. There are also fluoride-labile protecting groups, such as Tmsec and Tmse esters. To ensure effective coupling between carboxyl and amino groups, protecting groups should be easily attachable and removable without affecting other peptide segments.

Why are N-terminal acetylation and C-terminal amidation modifications performed?

Chemically synthesized peptides often carry free amino and carboxyl groups. To mimic the native state of the peptide within the parent protein sequence more closely, the peptide termini are often capped, i.e., N-terminal acetylation and C-terminal amidation. These modifications reduce the overall charge of the peptide, decrease its solubility, and allow the peptide to simulate its original state of α-amino and carboxyl groups within the parent protein.

If N-terminal acetylation or C-terminal amidation modifications are required, please specify them when placing an order. Once synthesis is completed, modifications cannot be made.

Some Cases of Customized peptides

RP-HPLC

Mass Spec