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Peptide-Small Molecule Conjugates & Peptide Drug Conjugates (PDCs)

Custom peptide-payload conjugates with defined attachment sites, linker strategy selection, and analytics that confirm identity and purity.

Site-defined peptide-small molecule conjugation with controllable linker chemistry.

Request a Quote Service options Linker & chemistry
ISO 900:2015/ISO13485:2016 45+ Years of Expertise U.S. Facilities - Texas Site-specific conjugation Cleavable & non-cleavable linkers HPLC/LC-MS QC
Overview Services & keywords Chemistry Attachment sites Workflow QC FAQ Contact Reading

Overview

What are peptide-small molecule conjugates and PDCs?

Bio-Synthesis provides peptide-small molecule conjugation and peptide drug conjugation services for research and discovery, including peptide-antibiotic conjugates, peptide-inhibitor conjugates, and peptide-probe hybrids. By integrating in-house peptide synthesis with fit-for-purpose conjugation chemistry, we deliver reproducible PDCs supported by practical purification and analytical validation.

Peptide-small molecule conjugates are hybrid molecules formed by covalently linking a peptide to a small molecule payload. When the payload is a drug or pharmacologically active compound, these constructs are often described as peptide drug conjugates or PDCs (peptide-drug conjugates). The peptide component can provide targeting, uptake, stabilization, or spacing, while the payload contributes potency or functionality.

A successful peptide-small molecule bioconjugation project depends on three design decisions: (1) where the payload attaches (site specificity), (2) how it attaches (chemistry/handle selection), and (3) whether the payload should be released (cleavable linkers) or remain permanently linked.

Peptide drug conjugation Peptide-payload conjugates Peptide-small molecule hybrids Peptide-antibiotic conjugation Cleavable linker options Site-defined attachment
Peptide-drug conjugate (PDC) design showing targeting peptide, linker strategies (thiol-maleimide, cleavable linkers, click chemistry), and small-molecule payloads including drugs, antibiotics, inhibitors, and probes.
Figure: Peptide-drug conjugate (PDC) architecture illustrating targeting peptides, linker strategies, and representative small-molecule payloads.
Targeting & uptake

Receptor-binding peptides, CPPs, or tissue-homing motifs can bias payload exposure to relevant cells.

Linker control

Choose stable vs cleavable linkers based on whether intracellular payload release is required.

Analytical confirmation

Identity and conjugation efficiency are verified using HPLC/UPLC and LC-MS when feasible.

Related services: Peptide Modifications, Peptide Bioconjugation, Cleavable Linker Peptides.

Request a Quote See service options

Service options we support (small-molecule & drug conjugation)

Prefer a quick scan? Expand the categories below for representative payloads, typical payload type/function, and technical notes. Payload feasibility is project-dependent and driven by functional groups, stability, and the desired mechanism (stable vs cleavable).

biotin conjugation vitamin-peptide conjugates vitamin-oligonucleotide conjugation

Bio-Synthesis has particular expertise in hydrophobic vitamin conjugation, especially tocopherol (vitamin E) payloads, with spacer-assisted designs to maintain solubility and activity.

Payload Drug type Typical function / use Technical notes
Vitamin E (α-, β-, γ-, δ-tocopherols; tocotrienols) Hydrophobic vitamin Vitamin E delivery peptide constructs; membrane interaction and antioxidant biology studies Signature capability. Spacer-assisted coupling (e.g., PEG/alkyl) helps control aggregation and preserve peptide solubility; site-defined attachment recommended.
Vitamin A (retinoids) Fat-soluble vitamin Targeting / uptake studies; motif presentation Attachment strategy depends on available handle; linker length chosen to reduce steric masking.
Vitamin D (calciferols) Fat-soluble vitamin Targeting / mechanism studies Hydrophobicity may influence purification; consider spacer and solvent system.
Vitamin K (phylloquinone/menaquinone) Fat-soluble vitamin Targeting / pathway probes Often benefits from spacer/linker architectures to reduce aggregation and steric interference.
Vitamin B-complex (B1 thiamine, B2 riboflavin, B6 pyridoxine, B12 cobalamin) Water-soluble vitamins Receptor-mediated uptake, transport studies, assay development Bulky cofactors (e.g., B12) commonly use defined peripheral handles to preserve binding motifs.
Vitamin C (ascorbic acid) Water-soluble vitamin Proof-of-concept conjugation; redox biology tools Oxidation sensitivity considered during route selection and purification.
Biotin (B7), Folate (B9) Affinity / targeting handles Biotin peptide conjugation (avidin/streptavidin capture); folate receptor targeting Common for peptide/protein/oligo labeling; stoichiometry can be controlled by handle design.

Dedicated landing page: Vitamin Conjugation

peptide-antibiotic conjugation antibiotic peptide conjugates stable or cleavable
Payload Drug type Typical function / use Technical notes
Amoxicillin, Ampicillin β-lactams Antibiotic-peptide conjugates for uptake/targeting studies Handle selection tuned to preserve β-lactam integrity; site-defined coupling recommended.
Tetracycline Tetracyclines Model antibiotic payloads and delivery studies Protect labile motifs as needed; define linker/spacer to control orientation and loading.
Streptomycin, Gentamicin (Gentamycin) Aminoglycosides Highly polar antibiotics; mechanistic probes Polycationic nature affects purification; analytical strategy is project-dependent.
Chloramphenicol, Du-6859a Broad-spectrum antibiotics Assay tools and proof-of-concept conjugates Avoid harsh conditions to maintain aromatic nitro stability; confirm integrity by LC methods as appropriate.
Sulfonamide group: Sulfamethazine, Sulfadiazine, Sulfafurazole, Sulformetoxine, Sulfamethoxypyridazine, Sulfaguanidine, Sulfathiodiazole, Sulfamethoxazole, Sulphamethoxydiazine, Sulfamonomethoxine, Madribon, Sulfaquinoxaline Sulfonamides Class-wide antimicrobial payload coverage Primary amines and sulfonyl motifs enable controlled coupling; confirm handle position to minimize heterogeneity.
Clenbuterol, Ractopamine, Salbutamol β-agonists Detection/enrichment; immunoassay and capture standards Often conjugated to peptides/proteins for ELISA/capture workflows; define loading to match assay needs.

Dedicated landing page: Peptide-Antibiotic Conjugation

peptide drug conjugates peptide-payload conjugates oncology payloads
Payload Drug type Typical function / use Technical notes
Anthracyclines: Doxorubicin, Epirubicin, Daunorubicin, Idarubicin, Elsamicin A DNA-intercalators Representative oncology payloads for peptide drug conjugates (PDCs) Linker selection driven by stability vs release; evaluate payload sensitivity to conjugation and purification conditions.
Antitumor antibiotics: Actinomycin D, Bleomycin, Mithramycin, Mitomycin DNA-binding / cleavage Mechanistic tools and cytotoxic payload exploration Avoid harsh conditions; evaluate oxidative/hydrolytic stability during route selection.
Taxanes: Taxol (Paclitaxel), Docetaxel, Tesetaxel Microtubule agents Hydrophobic cancer-drug payloads Hydrophobicity impacts purification/solubility; spacer (e.g., PEG) often improves handling.
Vinca alkaloids: Vincristine, Vinblastine, Navelbine (Vinorelbine) Microtubule agents Cytotoxic payloads for targeted delivery constructs Site-defined handles reduce heterogeneity and help control drug-to-peptide ratio.
Topoisomerase agents: Etoposide (VP-16; also written “Etoposie”), Irinotecan, Topotecan Topo inhibitors DNA/topo-targeting payloads Assess stability and reactive handles; set acceptance criteria for loading and purity.
Platinum drugs: Cisplatin, Carboplatin DNA crosslinkers DNA-damaging payload class Coordination chemistry affects route choice; confirm compatibility with buffers and carrier residues.
Alkylators / mustards / nitrosoureas: Busulfan, Nitrogen mustards, Uramustine, Chloroambucil, Melphalan, Cyclophosphamide (also written “Cyclophophamid”), Ifosfamide, Carmustine, Lomustine, Semustine, Procarbazine, Dacarbazine Alkylating agents Release-mechanism and stability studies in PDCs Payload stability and available functional groups guide coupling strategy (stable vs cleavable).
Antimetabolites / nucleoside analogs: Methotrexate, Pemetrexed, Mercaptopurine, Thioguanine, Ara-C (Cytarabine), Gemcitabine, Capecitabine, Tegafur-uracil, Nelarabine, Fludarabine, Leustatin (Cladribine), Hydroxyurea, Lamivudine Antimetabolites Drug-peptide conjugates and peptide-small molecule hybrids Route selected to preserve labile motifs; handle planning prevents multi-site labeling.
Targeted inhibitors & other small molecules: Erlotinib, Lapatinib, Mitoxantrone, Praziquantel, Ambroxol, Demecolcine, CCP (3-cyano-2-chloropyridine) Mixed Target engagement, probes, proof-of-concept payloads Conjugation site chosen to maintain pharmacophore exposure; spacer length often optimized.
Biologics (typically carriers): Bevacizumab (Avastin; also written “Beacizumab”), Rituximab, Tumor necrosis factor (TNF) Proteins / antibodies Often used as targeting carriers rather than “small-molecule payloads” We support site-selective antibody/protein workflows when your project requires them (project-dependent).

Broader payload menu: Drug Modification & Conjugation

peptide-small molecule hybrids custom peptide small molecule conjugate proof-of-concept
Payload Drug type Typical function / use Technical notes
Aspirin, Ibuprofen, Ketoprofen NSAIDs Model small molecules for conjugation workflows Often coupled via amide/activated ester routes depending on handle availability.
5-Azacytidine Nucleoside analog Proof-of-concept conjugation and stability studies Stability considerations drive route selection and purification conditions.
Lisinopril, Pravastatin Small-molecule drugs Delivery/mechanism studies Handle planning prevents multi-site labeling; QC aligned to intended use.
Memantine HCl, Propranolol CNS / cardio drugs Model payloads for drug-peptide conjugates Ionizable groups can affect HPLC behavior; method selection adjusted accordingly.

Not listed? Send structure or catalog number + desired attachment site/chemistry-our team will recommend a practical route.

Keyword coverage & feasibility note

This page targets: custom peptide small molecule conjugate, peptide small molecule conjugation, peptide drug conjugate, peptide-drug conjugates (PDCs), peptide-payload conjugates, peptide-small molecule hybrids, peptide-antibiotic conjugation, antibiotic peptide conjugates, vitamin conjugation, and biotin conjugation. Also covered: peptide vitamin E conjugation, tocopherol peptide conjugate, vitamin E delivery peptide, hydrophobic vitamin conjugation, and vitamin B12 peptide conjugation.

For broader payload menus, see Drug Modification & Conjugation. For category-specific hubs, see Peptide-Antibiotic Conjugation and Vitamin Conjugation.

Linker and conjugation chemistry

Thiol-maleimide (Cys-selective)

Efficient 1:1 coupling when a single cysteine is available.

  • Stable thioether linkage
  • Good for early prototypes
  • Minimize multi-Cys heterogeneity
Click chemistry (SPAAC / CuAAC)

Bioorthogonal coupling using azide/alkyne handles; SPAAC avoids copper exposure.

  • High selectivity
  • Compatible with complex payloads
  • Ideal for site-defined constructs
Amide coupling (NHS/EDC)

Direct carboxyl-amine coupling when a unique handle is available.

  • Simple chemistry
  • Handle planning required
  • Avoid multi-amine mixtures
Cleavable linkers (project-dependent)

Used when intracellular payload release is required.

  • Disulfide (reducible)
  • Enzyme-cleavable (protease-sensitive motifs)
  • pH-labile linkers
Non-cleavable linkers

Preferred when the goal is stable, permanent linkage for imaging or mechanistic studies.

  • Stable thioether or triazole linkages
  • Reduced risk of premature release
  • Often simplifies interpretation

Site-specific attachment options

N-terminal conjugation

Simple, controllable attachment when compatible with peptide function.

  • Often supports 1:1 stoichiometry
  • Compatible with NHS/click strategies
  • Low heterogeneity risk
C-terminal conjugation

Useful when N-terminus must remain free; implemented via engineered handles.

  • Preserves N-terminal motifs
  • Handle planning recommended
  • Works with click/amide routes
Cys-selective attachment

Preferred for strict site-definition when a single cysteine is present.

  • Thiol-maleimide standard
  • Disulfide possible (cleavable)
  • Avoids multi-Lys mixtures

Workflow: From Concept to Conjugate

Design review
Sequence • payload handle • linker goal
Synthesis & conjugation
Site-defined coupling • cleavable vs stable
Purification, QC & delivery
HPLC/UPLC • LC-MS (feasible) • COA
Design review
Sequence • payload handle • linker goal
Synthesis & conjugation
Site-defined coupling • cleavable vs stable
Purification, QC & delivery
HPLC/UPLC • LC-MS (feasible) • COA
Figure: Workflow for peptide–small molecule conjugation (PDCs), from design to purification, QC, and documentation.

Quality control & typical deliverables

Standard QC
  • Analytical HPLC/UPLC purity profile
  • Identity confirmation (LC-MS when feasible)
  • COA + method summary
Conjugation efficiency
  • Conjugation ratio / conversion reporting
  • Residual starting-material check
  • Optional orthogonal methods (project-dependent)
When to add more

If your decision depends on release kinetics or stability, tell us and we’ll align methods to it.

FAQ

Do you offer peptide-antibiotic conjugation?

Yes-peptide-antibiotic conjugates and related antibiotic-peptide conjugates are supported with site-defined attachment and linker strategies selected for your objective.

Can you make cleavable linkers?

Yes-disulfide, enzyme-cleavable, and pH-labile linkers are supported when release is required (project-dependent).

How do you confirm conjugation?

Typical confirmation includes analytical HPLC/UPLC, LC-MS when feasible, and conjugation ratio reporting.

What do you need to start?

Send the peptide sequence, payload structure/name, desired attachment site (or constraints), quantity/purity, and intended use.

Do you offer vitamin E \(tocopherol\) peptide conjugation\?

Yes. We routinely prepare tocopherol (vitamin E) peptide conjugates with site-defined attachment and spacer-assisted architectures to manage hydrophobicity. Tell us the tocopherol form (α/β/γ/δ or tocotrienol), desired linkage (stable vs cleavable), and your solubility constraints.

More FAQ'sAll FAQ's

Contact & quote request

For the fastest quote, send your peptide sequence(s), payload/drug name (and structure or catalog number if available), desired attachment site (or constraints), stable vs cleavable preference, quantity/purity targets, and intended use. We’ll recommend a practical conjugation route plus purification/QC aligned to your application.

Fastest path
Request a Quote Review services

What happens next: Our technical team typically reviews requests within 1 business day and responds with feasibility notes, recommended chemistry/linker options, a QC plan, and pricing.

Fast quote checklist
  • Peptide sequence(s) + terminal state (free vs capped) and any Cys/handles
  • Payload name + structure (or catalog number) and known functional groups
  • Preferred chemistry (or “recommend”) and stoichiometry goal
  • Stable vs cleavable linker preference (if any)
  • Quantity (mg) + purity target + intended use

If you’re not sure which coupling is most robust, share the payload functional groups-our team will recommend a handle + linker plan to minimize heterogeneity and confirm identity by fit-for-purpose analytics.

Recommended Reading

The following peer-reviewed articles provide useful background on peptide-small molecule conjugates, peptide drug conjugates (PDCs), linker strategies, and payload selection considerations.

  • Peptide-Drug Conjugates: Design, Synthesis, and Biomedical Applications
    Bioengineering (2025), 12(5), 481.
    Comprehensive review covering PDC architectures, linker chemistry, and therapeutic design considerations. Read article
  • Peptide-Drug Conjugates as Targeted Therapeutics
    Overview of targeting peptides, payload selection, and cleavable vs non-cleavable linkers in PDC design. Advanced Drug Delivery Reviews.
  • Linker Strategies in Peptide and Protein Conjugation
    Discussion of amide, thiol-maleimide, click, and stimuli-responsive linkers relevant to peptide-small molecule conjugates. Bioconjugate Chemistry.
  • Design Principles for Peptide-Based Targeted Drug Delivery
    Reviews peptide targeting motifs, stability considerations, and translational challenges in peptide conjugates. Journal of Controlled Release.

These references are provided for background and design insight; Bio-Synthesis does not claim ownership of the cited works.

Why Choose Bio-Synthesis

Trusted by biotech leaders worldwide for over 40+ years of delivering high quality, fast and scalable synthetic biology solutions.

Greetings Researchers,

Please be advised that any information, guidelines, writeups, and oral/video/graphic content on our website are intended solely as general guidelines.
It is the researcher's sole responsibility to conduct thorough research on the designs of the products intended for their experiments before submitting
their designs to Biosynthesis for review of production feasibility.
Thank you for your understanding.

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