Custom Peptide Synthesis Services

• Architectures & Modalities: Linear, branched, cyclic, stapled, and bicyclic peptides, including PEGylated formats and advanced peptidomimetics—engineered for both custom and library-based discovery programs.
• Challenging Sequences: Disulfide rich, boronic acid, conformationally constrained.
• Backbone Engineering: DAAs, N-methylations, unnatural AAs, THF amino acids in SPPS for stability & bioactivity.
• Long Peptides & Protein Fragments: NCL/KAHA ligation for extended sequences (>150 AAs).

Modified Peptide Synthesis (Discovery Grade Customization)

PeptAR_x offers a full spectrum of peptide modification strategies to optimize stability, functionality, and performance for your program:

• Terminal Engineering: Precise N-terminal and C-terminal modifications for enhanced peptide integrity
• Smart Labeling: Fluorescent dyes, biotin tags, and isotope incorporation for imaging and analytical studies
• PEGylation & Conjugation: Improve solubility, pharmacokinetics, and targeted delivery
• Biological Mimics: Late-stage modifications such as phosphorylation, sulfation, and glycosylation, oxidative folding
• Chelator Integration: DOTA/NOTA for radiolabeling and diagnostic applications

Beyond side-chain and backbone customization, we seamlessly integrate unnatural amino acids into sequences—expanding chemical space and unlocking new therapeutic possibilities.

For more information on our catalogue of unnatural amino acid products (500+), please CONTACT US.

Cyclic & Macrocyclic Peptide Expertise

Cyclization is a proven approach to improve peptide potency, stability, and target engagement. PeptARx, Aragen’s integrated peptide platform, offers end-to-end capabilities for cyclic and macrocyclic peptides—covering molecular design, synthesis, analytical characterization, and scale-up to advance complex peptide programs.

With deep expertise in macrocyclization, delivering more than 2,500 cyclic peptides annually across a wide range of structural complexities and design requirements.

Cyclization Chemistries

• Lactam cyclization (mono‑ and bi‑cyclic)
• Lactone formation
• Disulfide bridge formation (single, double, triple)
• Thioether cyclization (mono‑ and bi‑cyclic)
• Click‑based cyclization
• Ring‑closing metathesis (RCM)
• Metal‑catalyzed C–C bond formation (Suzuki, Heck, olefin metathesis)

Orthogonal Protection Strategies

• Allyl/Alloc, Dde, Mtt, and Pmb protecting groups
• Controlled formation of multiple bridges and complex cyclic architectures

Cyclization Positions Supported

• Head-to-tail
• Head-to-side chain
• Side chain-to-side chain
• Side chain-to-tail

Library Synthesis & Parallelization (High-Throughput Discovery)

Coupled with robust analytical workflows, we consistently deliver peptides at exceptional purity—up to 99.9%—meeting stringent research and development standards.

Backed by extensive experience, our team has successfully produced [1500+] linear peptides and [2500+] cyclic peptides, along with numerous complex modifications, over recent years.

• Tooling: Automated synthesizers (CEM MultiPep 2, Liberty Blue 2.0; Biotage Alstra; SYMPHONY® X-24; PTI Prelude); 48-station SiliCycle block.
• Approach: Parallel & sequential synthesis; microwaveassisted coupling; combined automated/manual strategies for long or difficult peptides.
• Outcome: Rapid crudetopure workflows with inprocess LCMS/HPLC checks for faster iteration.

Advanced Peptide Synthesis

We support the following advanced peptides.

• Ligated Peptide
• Branched Peptides
• Dendrimers
• Peptide Nucleic Acids (PNA)
• Peptoid
• Peptidomimetics, and more

Specialized Reactions on Solid Support

• Suzuki Coupling
• Sonogashira Coupling
• Heck Reaction
• Reductive Amination
• Reduction/Oxidation, and more