Custom peptide synthesis for research projects ranging from standard peptide sequences to larger, modified, and technically challenging peptides.
Celtek Peptides provides peptide synthesis services for universities, research institutes, biotechnology companies, and pharmaceutical research teams. Projects can be configured around the sequence, quantity, purity level, modifications, and analytical requirements needed for the research.
Our goal is straightforward: provide researchers with a clearly characterized peptide and the documentation needed to understand what was synthesized.
For custom projects, the best place to start is with the peptide sequence and the amount and purity you need. From there, Celtek can review the project for synthesis feasibility, modifications, purification requirements, and analytical testing.
Request a Custom Peptide Quote
Custom Peptide Synthesis Services
Not every research project needs the same peptide.
Some experiments only require a few milligrams of a relatively short, unmodified sequence. Others require higher purity, unusual amino acids, terminal modifications, cyclization, longer sequences, or much larger quantities.
Celtek’s custom peptide synthesis services are designed to accommodate those differences.
Current service capabilities include:
- Custom peptide sequences
- Milligram, gram, and larger-scale projects
- Multiple purity levels from desalted material through >98% purity
- Peptides up to 100 amino acids, subject to sequence feasibility
- Unusual and modified amino acids
- Phosphorylated peptides
- Biotinylated peptides
- Terminal modifications
- Cyclic peptides
- Specially designed research peptides
- HPLC purification
- HPLC purity analysis
- Mass spectrometry analysis
- Additional analytical testing by request
- Lyophilized peptide delivery
Difficult sequences and unusual projects should be reviewed individually before a quotation is finalized.
Choose the Peptide Purity Your Research Requires
Higher purity is not automatically necessary for every experiment.
Purifying a peptide further requires additional processing and can affect cost, yield, and turnaround time. The appropriate purity therefore depends on what the peptide will be used to study.
Celtek currently offers custom peptide synthesis at several purification levels:
| Purity Option | General Consideration |
|---|---|
| Desalted | Useful when extensive purification is not required |
| >70% | Lower-purity research material |
| >80% | Exploratory and qualitative research |
| >90% | Cleaner material for more selective research applications |
| >95% | Higher-purity material for assays where impurities may affect results |
| >98% | High-purity projects with tighter analytical requirements |
If you are unsure which purity level makes sense, the downstream application is usually the best place to start.
For example, a preliminary screening experiment may not need the same purity as an assay in which small amounts of peptide-related impurities could interfere with measurement.
Choosing the appropriate purity rather than automatically choosing the highest available grade can also make a project more practical.
Peptide Quantity From Milligrams to Larger Scales
Custom synthesis requirements can change substantially as a research program develops.
Early experiments may require only a few milligrams. Once a sequence has been validated, the same research group may need larger quantities for expanded experiments or continued development.
Celtek supports peptide synthesis across multiple quantities, including:
Milligram scale for smaller research projects.
Gram scale for projects requiring substantially more material.
Larger-scale synthesis for projects that move beyond routine laboratory quantities, subject to project review.
Quantity is one of the main factors that affects both synthesis planning and pricing. Larger orders may require a different production approach than a small research batch.
If a project may eventually need substantial quantities, it is useful to mention that during the initial discussion even if the first order is small.
Modified and Unusual Peptides
A peptide sequence does not always consist only of standard amino acids.
Researchers often modify peptides to change their biochemical properties, provide an experimental label, enable conjugation, study a specific post-translational modification, or create a different molecular structure.
Celtek’s custom peptide synthesis capabilities include modifications such as:
- unusual amino acids
- phosphorylation
- biotinylation
- N-terminal and C-terminal modifications
- cyclization.
Modified peptides should be reviewed individually because synthesis difficulty can depend heavily on the sequence and the location and type of modification.
A modification that is simple on one sequence may create a more difficult synthesis or purification problem on another.
Large and Difficult Peptide Sequences
Peptide synthesis generally becomes more challenging as sequences become longer and more chemically complex.
Hydrophobicity, aggregation, repeated residues, difficult coupling steps, unusual amino acids, and particular sequence motifs can all affect synthesis and purification.
Celtek currently lists custom peptide synthesis for sequences up to 100 amino acids, although feasibility should be reviewed before treating that number as an automatic limit for every sequence.
That distinction matters.
A relatively straightforward long sequence and a shorter but highly hydrophobic or heavily modified sequence can present very different manufacturing problems.
For longer or difficult peptides, provide the full sequence when requesting a quote so the project can be evaluated before production begins.
Peptide Purification by HPLC
Synthesis produces the target peptide along with peptide-related byproducts that may result from incomplete reactions, deletion sequences, side reactions, or other synthesis processes.
Purification separates the desired peptide from these unwanted components.
Celtek uses high-performance liquid chromatography, or HPLC, for peptide purification, including reversed-phase chromatography.
The amount of purification required depends partly on the requested final purity.
A desalted peptide requires much less purification than a peptide specified at >95% or >98%.
This is one reason purity level affects both project complexity and price.
HPLC and Mass Spectrometry Analysis
Purity and identity are related, but they are not the same measurement.
For custom peptide projects, Celtek currently provides both HPLC analysis and mass spectrometry analysis with the synthesized peptide.
HPLC helps characterize the chromatographic purity of the final peptide.
Mass spectrometry provides evidence that the molecular mass of the material corresponds to the expected peptide.
Using both methods provides more information than relying on a purity percentage alone.
A peptide could produce a strong HPLC purity result while still requiring an identity measurement to establish that the major component is the expected molecule.
Each custom peptide is also accompanied by a synthesis report.
Additional analytical work, including amino acid analysis or sequencing analysis, may be available when a project requires it.
Lyophilized Peptide Delivery
Custom peptides are normally supplied in lyophilized form.
Lyophilization removes water from a frozen material under reduced pressure, producing the dry peptide material commonly supplied by peptide synthesis laboratories.
The appropriate storage and handling conditions still depend on the specific peptide.
Sequence, modifications, oxidation sensitivity, hygroscopicity, and other molecular properties can influence stability.
Researchers should therefore treat storage requirements as peptide-specific rather than assuming that every lyophilized peptide behaves identically.
How Long Does Custom Peptide Synthesis Take?
Most standard custom peptide projects are currently estimated at approximately 2 to 3 weeks after an official order is received.
That should be treated as a typical timeline rather than a guarantee for every sequence.
Longer peptides, difficult sequences, special modifications, larger quantities, unusually high purity requirements, or additional analytical work can increase the project timeline.
If a deadline matters to the experiment, include it when requesting the quotation so feasibility can be assessed before the order is placed.
What Affects Custom Peptide Synthesis Pricing?
There is no single useful price for custom peptide synthesis because the difficulty of two peptides of the same length can be very different.
The main variables include:
Sequence length. Longer sequences generally require more synthesis steps.
Requested quantity. Producing 5 mg and producing several grams are different projects.
Purity. Higher-purity peptides require more extensive purification.
Sequence difficulty. Hydrophobic, aggregation-prone, unusual, or otherwise difficult sequences may require additional work.
Modifications. Phosphorylation, biotinylation, unusual amino acids, cyclization, and other modifications can change synthesis complexity.
Analytical requirements. Additional testing beyond the standard synthesis report, HPLC, and mass spectrometry can affect the quotation.
Because of those variables, I recommend that the new Celtek page use project-specific quotations rather than the legacy fixed price-per-residue table.
That keeps the pricing accurate and avoids quoting a standard price for a peptide that turns out to require substantially different chemistry.
Information to Include With a Quote Request
A complete request makes it easier to evaluate the peptide correctly the first time.
When contacting Celtek about custom peptide synthesis, include as much of the following information as possible:
- Peptide sequence
- Desired quantity
- Required purity
- N-terminal or C-terminal requirements
- Any unusual amino acids
- Phosphorylation, biotinylation, cyclization, or other modifications
- Any special analytical requirements
- Number of different sequences
- Expected project timeline
- Any known sequence or solubility concerns
If you are not sure about the appropriate purity or specification, include the intended research application. That gives the synthesis team more context when reviewing the project.
Custom Peptides for Research Applications
Celtek has experience with the design and synthesis of peptides used across biochemical and cell-based research.
Projects may include peptides designed for areas such as:
- enzyme research
- antigenic peptide research
- receptor and ligand studies
- cell-signaling research
- peptide transport and intracellular delivery research
- cell-penetrating peptide research
- biochemical assay development.
Celtek’s history in cell-penetrating peptide research is especially relevant here. The company’s scientific work has included peptide technologies designed to influence intracellular delivery and signaling pathways.
Custom peptide synthesis services are provided for legitimate laboratory research and development applications.
Why Sequence Review Matters Before Synthesis
A peptide order is more than a sequence and a requested number of milligrams.
The actual sequence can influence:
- synthesis difficulty
- expected yield
- purification
- solubility
- stability
- modification strategy
- analytical interpretation.
That is why technically challenging custom peptide projects should be reviewed before production rather than treated as interchangeable catalog products.
A short feasibility discussion can identify potential issues before synthesis begins.
Frequently Asked Questions
What purity levels are available for custom peptides?
Celtek currently lists desalted, >70%, >80%, >90%, >95%, and >98% purity options. The appropriate level depends on the requirements of the research.
How are custom peptides tested?
Custom peptide projects include a synthesis report along with HPLC and mass spectrometry analyses. HPLC helps characterize purity, while mass spectrometry supports confirmation of peptide identity.
Can Celtek synthesize modified peptides?
Yes. Current capabilities include unusual amino acids, phosphorylation, biotinylation, terminal modifications, and cyclization. Other technically complex sequences should be reviewed individually.
How long can a custom peptide be?
Celtek currently lists synthesis of large peptides up to 100 amino acids. Sequence feasibility still matters, so longer and difficult peptides should be evaluated before the order is finalized.
What quantities are available?
Custom synthesis can cover milligram and gram quantities, with larger-scale projects available for review and quotation.
How long does custom peptide synthesis usually take?
A standard project is generally estimated at about 2 to 3 weeks after the order is received. Complex sequences, modifications, high-purity projects, or larger scales may take longer.
How much does custom peptide synthesis cost?
Cost depends on sequence length, quantity, purity, sequence difficulty, modifications, and analytical requirements. A project-specific quotation is the more accurate way to price custom peptide synthesis.
Are the peptides supplied lyophilized?
Celtek currently supplies custom peptides in lyophilized form.
Request a Custom Peptide Synthesis Quote
Send Celtek the peptide sequence along with the required quantity, purity level, modifications, and any special analytical requirements.
For unusual or difficult sequences, include as much information about the intended research project as possible. The sequence can then be reviewed before a final specification and quotation are established.
Request a Quote
For Research Use Only. Not for human or veterinary use. Not for diagnostic or therapeutic use.