Custom Peptide Synthesis
Custom Peptide Synthesis Services | Advanced Modifications, Conjugation & Expertise
Peptide Services
Custom Peptide Synthesis
Sinopep offers flexible, high-quality custom peptide synthesis services designed to meet the diverse needs of researchers at every stage of development. We synthesize peptides ranging from 2 to 110 amino acids using advanced Fmoc solid-phase synthesis and purify them through high-performance liquid chromatography (HPLC). Our capabilities span from small-scale milligram production to multi-kilogram manufacturing, with purity options from crude to >98%, based on project requirements.
With deep expertise and state-of-the-art facilities, Sinopep is committed to delivering peptides with precision, reliability, and consistency—no matter the sequence complexity. From standard synthesis to complex modifications, formats, and scales, our team works closely with you to provide tailored solutions.
Peptide Modifications & Conjugations
Comprehensive Technical Overview of Advanced Cyclic Motifs, Bio-Conjugates, PTM Mimics, and Specialty Formats
| Category | Modifications & Technologies | Applications |
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| Cyclization & Constraints |
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| Conjugation & Labels |
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| Unnatural & PTM Mimics |
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| Specialized Formats |
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Quality
Peptide Quality Control
At Sinopep, quality control is a fundamental pillar of our custom peptide synthesis process. Each peptide we produce undergoes rigorous analysis to confirm its identity, purity, and consistency. Standard analytical techniques include LC-MS, MALDI-MS, and HPLC, ensuring reliable characterization of every peptide product.
We provide a comprehensive analytical data sheet along with corresponding raw data for each order. All documentation is thoroughly reviewed and archived before shipment to maintain full traceability and compliance with regulatory standards.
Our standard QC includes:
- LC-MS with ion trap, quadrupole, or TOF detection
- MALDI-MS
- Analytical and preparative HPLC
In addition, Sinopep offers a wide range of optional peptide analysis services tailored to your project needs, including:
- Amino acid analysis (AAA)
- Peptide sequence verification via mass spectrometry
- Residual solvent and moisture content determination
- Solubility and stability testing
- Toxicity, sterility, endotoxin, and bioburden testing
- Nuclear magnetic resonance (NMR) analysis
- And more customized assays upon request
With Sinopep, you can trust that your peptides are produced with precision and backed by industry-leading quality assurance.
Purity
Peptide Purity Levels – Applications at a Glance
To determine the appropriate peptide purity for your project, please reference the table below.
| ≥ 70 % Purity (Immuno-Grade) Cost-effective, high-throughput applications |
≥ 80 % Purity (Research-Grade) Early discovery & non-quantitative work |
≥ 95 % Purity (High-Purity Assay Grade) Sensitive, quantitative, & reproducible studies |
≥ 98 % Purity (Ultra-High / GMP-like) Advanced R&D and clinical development |
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| Immunogen for polyclonal & monoclonal antibody production | Enzyme-substrate interaction screening | Quantitative ELISA, RIA, & DELFIA standards | Structure-Activity Relationship (SAR) studies |
| ELISA reference standard for antiserum titer screening | Phosphorylation & kinase activity assays | Precise receptor-ligand binding assays (SPR, ITC, etc.) | X-ray crystallography & cryo-EM grade material |
| Competitive elution chromatography | Peptide blocking & inhibition experiments | In vitro bioactivity & functional assays | High-resolution mass spectrometry & peptide mapping |
| Peptide array / epitope mapping production | Affinity resin coupling & pull-down studies | In vivo efficacy & pharmacokinetic studies | Clinical-trial materials & IMPD/IND-grade peptides |
| Carrier protein conjugation trials | Cell adhesion & tissue-culture plate coating | Quantitative enzymatic kinetics | Active Pharmaceutical Ingredients (API) for commercial therapeutics |
| — | Protein gel electrophoresis & Western blot standards | Structural biology prep for NMR & initial MS experiments | Final commercial products & reference standards |
Custom Peptide Synthesis FAQs
What's the difference between gross and net peptide weight?
Unless otherwise specified, all peptides are delivered based on gross weight. This includes not only the peptide itself but also peptide-related impurities, salts, counter ions, residual solvents, and water. In contrast, net peptide refers solely to the actual peptide content. In some experiments, knowing the net peptide amount is crucial, as peptide content can vary significantly depending on the specific sequence.
How does Sinopep conjugate peptides to carrier proteins for antibody production?
In peptide-antibody production, carrier proteins are essential for eliciting a strong immune response. KLH is preferred over BSA due to its higher immunogenicity. Using BSA may generate antibodies against both the peptide and BSA, potentially skewing ELISA results.
For effective coupling, we recommend adding an N-terminal cysteine to the peptide. This allows for site-specific conjugation using MBS (maleimidobenzoic acid-N-hydroxysuccinimide ester) as a crosslinker. The process involves activating the carrier protein with MBS, removing excess crosslinker via SEC, then coupling to the peptide’s cysteine through a disulfide bond—achieving >95% efficiency. The only byproduct, salt, is removed by gel filtration.
As an alternative, peptides can be coupled to carrier proteins via amino groups using glutaraldehyde. This method typically yields ~80% efficiency. However, careful control of crosslinker concentration is critical to avoid unwanted protein–protein or peptide–peptide crosslinking.
Can Sinopep aliquot my products?
Aliquoting Services
Sinopep can aliquot any order to your specifications. By dividing your peptide into smaller quantities, this service enhances convenience, supports protocol standardization, and significantly improves long-term stability. It helps prevent contamination from frequent container openings, which can introduce moisture and lead to bacterial degradation, oxidation, or aggregation—ultimately compromising peptide purity and consistency across experiments.
Aliquots of 1 mg or more are measured by balance, while those under 1 mg are aliquoted volumetrically for greater precision.
