Macrocycles built for stability, binding, and real-world assay conditions.
A cyclic peptide is a peptide constrained into a ring by connecting the backbone (N-to-C head-to-tail) and/or side chains (e.g., disulfide or lactam bridges). This conformational constraint can sharpen a peptide’s bioactive shape, improving protease resistance, solution stability, and often target affinity compared with linear analogs. Cyclic and macrocyclic peptide designs are widely used in drug discovery, epitope/vaccine research, and assay development because they can better mimic structured binding motifs and retain performance in challenging matrices.
Bio-Synthesis manufactures cyclic peptides and macrocyclic peptide constructs using practical cyclization routes (head-to-tail, disulfide, lactam bridges, and stapling) with optional labels/handles (biotin, fluorophores, azide/alkyne click chemistry, cysteine handles) and a fit-for-purpose QC strategy. We don’t just “close the ring”—we engineer manufacturable designs: selecting cyclization sites, protecting-group strategy, and purification/QC to match your goal (screening, assay-grade, or immunization) and to reduce risk from aggregation, isomers, or solubility limits.
Ring closure can lock in bioactive shapes, improving potency and selectivity (sequence-dependent).
Cyclization can reduce proteolysis and increase stability in biological matrices.
Supports non-natural amino acids, labels, and handles when compatible with the cyclization chemistry.
Figure: Common peptide cyclization strategies used in custom cyclic and macrocyclic peptide synthesis.
Related services: Custom Peptide Synthesis, Peptide Modifications, Peptide Bioconjugation. For ready-made options, browse Catalog Peptides .
Backbone cyclization for compact macrocycles and improved protease resistance.
Cys–Cys loop formation with controlled oxidation conditions.
Amide bond between side chains (e.g., Lys/Asp or Lys/Glu) for robust constraints.
Hydrocarbon stapling or related constraints for α-helical stabilization (project-dependent).
When needed, multiple constraints can be used to refine conformation and potency.
Most cyclic peptide delays come from choosing a cyclization strategy that conflicts with sequence behavior (aggregation, sterics, or solubility). Share your goal (assay vs screening vs immunization), and we’ll recommend practical cyclization sites, ring size, and QC.
If your sequence is “difficult,” see Difficult Peptide Synthesis.
Confirm cyclization route, sites, modifications/handles, and success criteria.
Optimized coupling strategy for difficult segments; protect groups aligned to planned closure.
Ring closure (or oxidation) under controlled conditions, followed by purification and QC.
Typical cyclic peptide deliverables are sequence-dependent. For constrained or highly hydrophobic designs, we recommend fit-for-purpose purity/QC targets.
For peptides with disulfides, optional reduction/alkylation workflows can support confirmation when required.
If you need conjugation-ready cyclic peptides, see Peptide Bioconjugation.
Macrocycles for target engagement, inhibitor design, and SAR optimization.
Stable ligands and capture reagents with defined handles (biotin, click, dyes).
Constrained loops to mimic native epitopes and improve recognition.
Also explore: Peptide Arrays and Peptide Libraries.
The best method depends on your sequence, ring size, required conformation, and downstream use. Head-to-tail is common for backbone cyclization; disulfide is useful for cystine loops; lactam bridges add stability; stapling constrains helices. We review your design and recommend a practical route and QC plan.
Yes. We support non-natural amino acids, isotope labels, biotin, fluorescent tags, and functional handles (e.g., azide/alkyne, cysteine) when compatible with the cyclization chemistry and purification strategy.
Many cyclic peptides are HPLC-purifiable, but highly hydrophobic or aggregation-prone sequences may limit resolution. We align purity targets to your use case and recommend fit-for-purpose deliverables.
Cyclization is typically confirmed by mass spectrometry and chromatographic behavior. For disulfide patterns or complex conformations, additional methods (e.g., reduction/alkylation mapping or NMR) may be used when required.
Provide your sequence, desired cyclization type (or ask us to recommend), any modifications/handles, target quantity, and intended application. If you know solubility constraints or required purity/QC, include them to speed quoting.
A cyclic peptide is a peptide whose backbone or side chains are connected to form a ring (macrocycle). Cyclization can improve conformational control, protease resistance, and functional binding depending on sequence and target.
Share your sequence(s), preferred cyclization method (or “recommend”), any modifications/handles, quantity, and intended application. We’ll propose practical specifications and a synthesis/QC plan aligned to your goals.
Tip: If you’re comparing cyclic vs linear constructs, tell us your assay conditions and solubility constraints so we can recommend the best design.
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