Custom Peptide Libraries: Peptide Types We Offer and Their Applications

Understanding Custom Peptide Libraries and Their Research Value

What Are Custom Peptide Libraries?

Custom peptide libraries are systematically designed collections of peptides, ranging from a handful of focused analogues to many thousands of diverse sequences, where the list of members is defined by the researcher rather than chosen from a fixed inventory. Each member carries an explicit sequence, length, and (optionally) chemical modification, and the library as a whole is built around a stated scientific objective such as epitope mapping, structure-activity relationship (SAR) analysis, ligand discovery, or immunization. Compared with the broader category of screening libraries in drug discovery, custom peptide libraries emphasize sequence-defined content over random or natural-product diversity, making them especially well suited to programs where the researcher already knows (or suspects) the structural features they want to test.

How Should You Specify a Custom Peptide Library?

Specifying a custom peptide library well means turning a research question into a set of manufacturing decisions that the chemistry team can act on. The clearer the specification at the start, the fewer revisions are needed during synthesis and the more directly comparable the screening data will be. Most specifications fall into four interconnected blocks, and writing them down before the project starts almost always saves time later.

Sequence scope and length: state the parent sequence (if any), the variable positions, the chosen peptide length window (typically 6 to 30 residues for linear libraries, longer for long peptide synthesis projects), and any constraint on residue composition.

Purity tier and analytical package: define the per-peptide purity target (crude, desalted, ≥75%, ≥85%, ≥95%), the analytical methods each member must pass (HPLC, LC-MS, optional HRMS), and whether a pooled QC report or per-peptide certificate of analysis is required.

Modifications and labeling: list the chemical features that must be installed, including terminal caps, internal modifications, fluorescent or biotin labels, cyclization chemistry, and any conjugation handle.

Delivery format and timeline: choose between individual tubes, 96-well or 384-well plates, peptide or matrix pools, lyophilized powder or DMSO solution, and state the target delivery date relative to screening start.

A short consultation at the start of a project usually tightens these choices. Researchers who bring only the parent sequence and the screening format leave with a recommended library architecture, peptide length, offset, and modification strategy that has been used successfully on similar programs; researchers who already have a complete specification benefit from a feasibility review that flags problematic residues, expected difficult couplings, and any modifications that may need a representative pilot before the full library is committed.

Table.1 Typical Specification Parameters for Custom Peptide Libraries.

Sequence-Based Peptide Libraries for Epitope and Motif Studies

Sequence-based peptide libraries use the parent protein or peptide sequence itself as the variable. Each member represents a defined window of the natural sequence, and the library as a whole systematically covers the input. These formats are the workhorses of epitope mapping, motif identification, and any application where the researcher's starting point is a known sequence and the goal is to localize activity within it. Because every member can be traced back to a specific stretch of the parent protein, results are immediately interpretable and rarely need deconvolution.

Overlapping Peptide Libraries (8–25 mers, defined offset windows)

Design logic and features: overlapping libraries divide a parent protein into a series of peptides of equal length, each offset by a fixed number of residues from the previous one. Our standard configurations span 8 to 25 mers with defined offset windows — commonly 12- or 15-mers offset by 8 or 11 residues for antibody work, or shorter 9- to 11-mers for tight T-cell scans — ensuring that every possible linear stretch of the chosen window length appears at least once across the set. Offset choice is a deliberate balance: tighter offsets give finer resolution but increase the number of peptides, while wider offsets save material but may miss short motifs. For very large proteins, we support two-stage designs in which a first-pass screen at wide offset localizes the active region and a second-pass library at narrow offset pinpoints the critical residues.

Supported applications: overlapping libraries are the standard tool for B-cell epitope mapping, T-cell epitope scanning, and substrate-motif discovery, because a positive hit immediately localizes activity to a defined residue window without further deconvolution. They are equally at home in antibody specificity testing across protein families, in monitoring immune responses against whole antigens, and in kinase or protease substrate identification where a candidate recognition sequence must be traced back to a defined stretch of the parent protein.

Truncated Peptide Libraries (N- and C-terminal shortening series)

Design logic and features: truncated libraries are built by systematically shortening a parent peptide from one or both termini, generating nested sets that converge on the minimal active sequence. The library is delivered as three coordinated series — N-terminal truncations, C-terminal truncations, and (when requested) bidirectional shortening — each advancing one residue at a time from the parent. Because only the length varies while sequence identity is preserved, any change in activity can be attributed directly to the removed residues rather than to a change in composition. We can also build focused mid-region truncation series when the researcher already knows the boundaries of interest and only needs to explore internal length variation.

Supported applications: truncation libraries answer a different question than overlapping libraries do — not "where on the protein does activity reside?" but "what is the smallest version of this peptide that still works?". The answer is essential for peptide drug design, where every residue outside the active core adds synthesis risk, metabolic liability, and cost without contributing to efficacy. The minimal core defined by truncation also becomes the starting sequence that subsequent alanine scanning and positional scanning libraries explore in depth, making truncation a natural first step in most SAR campaigns.

Scrambled and Negative-Control Peptide Libraries (retained composition, randomized order)

Design logic and features: scrambled and negative-control libraries contain peptides that share the amino acid composition of an active parent sequence but differ in order, plus matched negative controls. Every active parent has at least one composition-matched scrambled partner, and every screening plate carries buffer, vehicle, and reverse-sequence controls alongside the active set. Because composition is retained while order is randomized, these libraries isolate the contribution of sequence order from the contribution of overall composition. Our design team will suggest an appropriate ratio of controls to actives (typically 1 control per 4 to 8 actives) so that statistical power and reagent cost both stay in a sensible range.

Supported applications: these libraries exist to validate that activity observed in the main library is truly sequence-specific. A binding or functional readout that survives an alanine scan, survives positional substitution, and disappears when the same residues are rearranged is far more convincing than the same readout in isolation, and scrambled libraries are the third leg of that validation tripod. They are routinely used alongside antimicrobial and cell-penetrating peptide studies, antibody binding confirmation, and any screening campaign whose conclusions depend on the specificity of the observed signal.

Table.2 Sequence-Based Peptide Library Offerings.

Substitution and Combinatorial Peptide Libraries for SAR Analysis

Substitution and combinatorial libraries move beyond the parent sequence and explore chemical variation. Each member of these libraries differs from a reference peptide at one or more positions, and the set as a whole maps how individual residues or residue classes contribute to activity. These formats power structure-activity relationship (SAR) studies, ligand optimization, and unbiased discovery campaigns where no prior motif is assumed. They are also the libraries most often paired with high-throughput screening, because their diversity is large enough to surface novel hits while still being sequence-defined enough to interpret any positive signal.

Alanine Scanning Peptide Libraries (single-position substitution sets)

Design logic and features: alanine scanning libraries substitute each non-alanine residue of a parent peptide with alanine, one position at a time, generating a single-position substitution set in which every member differs from the parent at exactly one residue. Alanine is chosen because it removes the side-chain functionality beyond a small methyl group without disrupting backbone conformation, so any drop in activity can be attributed to the loss of the original side chain rather than to a structural rearrangement. The libraries are deliberately small — only as many members as there are substitutable positions — which makes them cost-effective and fast to produce, and a representative pilot peptide is usually synthesized first to verify the parent sequence behaves as expected. Extended variants include D-amino acid or proline scans where the researcher wants to map backbone sensitivity in addition to side-chain sensitivity.

Supported applications: alanine scans give a residue-by-residue map of which positions tolerate substitution and which cannot be replaced without losing function — binary information (tolerated vs. essential) that most programs use to prioritize which positions deserve deeper exploration. They are a standard first step in peptide lead optimization, in antibody-epitope validation where "essential residue" data support a proposed binding model, and in mapping the contribution of individual side chains to receptor activation, enzyme inhibition, or membrane interaction.

Positional Scanning Peptide Libraries (defined-site mutation matrices)

Design logic and features: positional scanning libraries substitute each position of the parent peptide with a defined set of amino acids — commonly all 19 non-parent residues, or a curated panel of canonical substitutions grouped by physicochemical class — while the rest of the sequence is held constant. The result is a defined-site mutation matrix whose rows are positions and whose columns are substituent residues, covering hydrophobic, charged, polar, and sterically demanding chemistries at every site. The format also scales naturally into two-dimensional scans, where two positions are varied simultaneously to detect positional couplings that single-position scans miss. Libraries are larger than alanine scans but deliver far higher data density per peptide.

Supported applications: positional scanning is the format of choice for lead optimization on a known peptide scaffold and for kinase, protease, and phosphatase substrate motif definition. Where alanine scanning tells a researcher that a leucine is essential, positional scanning tells them that leucine, isoleucine, and valine are all tolerated but charged residues abolish activity — immediately pointing to a hydrophobic pocket on the binding partner. The same matrices support affinity maturation, selectivity engineering against homologous targets, and quantitative SAR datasets that feed computational models of peptide-target interaction.

Random and Combinatorial Peptide Libraries (10³–10⁶ diversity formats)

Design logic and features: random and combinatorial libraries are built when no prior motif exists and the library itself must surface one. Our standard diversity formats span 10³ members for focused randomized positions on a defined scaffold up to 10⁶–10⁹ members for fully randomized short windows, with library size chosen jointly with the screening format and the coupling quality achievable at each cycle. The classical construction is split-and-pool synthesis: the resin is split into N aliquots at each coupling step, each aliquot is coupled with one amino acid, and the aliquots are recombined before the next cycle, producing an equimolar mixture containing up to N^L distinct sequences. Pooling must preserve equimolarity, coupling completeness must be verified at every cycle, and shorter lengths with defined flanking residues are used when synthesis quality or screening throughput demands it.

Supported applications: combinatorial libraries require screening infrastructure capable of deconvoluting positive hits back to a defined sequence, and the common formats include bead-based affinity selection, one-bead-one-compound (OBOC) display with sequencing by Edman degradation or tandem mass spectrometry, and phage or mRNA display. They power unbiased ligand discovery against purified targets, novel motif identification for enzyme substrates or binding domains, and target-agnostic selection campaigns where the researcher wants the chemistry to reveal what the biology cannot yet predict.

Table.3 Substitution and Combinatorial Peptide Library Offerings.

Cyclic and Constrained Peptide Libraries for Improved Stability and Binding

Constraining a peptide into a defined secondary or tertiary structure is one of the most powerful levers available to peptide chemists. A cyclic or otherwise constrained peptide is shielded from exopeptidases, often more resistant to endopeptidases, and frequently gains binding affinity because its pre-organized structure pays a smaller entropy penalty upon engaging its target. Cyclic and constrained libraries are therefore the format of choice for any program where metabolic stability, membrane permeability, or tight binding is at a premium, including protein-protein interaction (PPI) targets, intracellular targets, and orally bioavailable peptide leads.

Disulfide-Bridged Cyclic Peptide Libraries (single and tandem Cys–Cys pairings)

Design logic and features: disulfide-bridged libraries install one or two disulfide bonds between cysteine residues, producing single-loop and tandem-loop constraint architectures. The library is delivered either as a series of peptides each carrying a single intramolecular Cys–Cys pair (the most common configuration), or as a more compact tandem format where two disulfide loops share cysteines to define a smaller, more rigid scaffold. Synthesis is fully compatible with Fmoc solid-phase workflows, using orthogonal cysteine protecting groups (Trt, Acm, StBu, Mob) that can be removed selectively when more than one bridge is required. Ring size is the most consequential design parameter: smaller rings (five to seven residues between the cysteines) favor defined turn structures, while larger rings accommodate more secondary structure and suit the mimicry of natural peptide loops.

Supported applications: these libraries underpin scaffold-based ligand discovery against receptors and enzymes, mimicry of natural disulfide-rich peptide families, and any program where a defined loop presentation is required for binding. Single-loop formats are common for receptor-antagonist and antibody-mimetic scaffolds, while tandem-loop formats suit more demanding targets where one loop does not provide enough binding surface. Reductive stability and oxidoreduction status are confirmed as part of the QC package, so that screening data reflect the constrained structure rather than a partially reduced mixture.

Stapled Peptide Libraries (hydrocarbon-stapled α-helical formats)

Design logic and features: stapled libraries introduce a hydrocarbon bridge between two non-natural residues placed on the same face of an alpha helix. The bridge locks the helix in place, dramatically increases proteolytic stability, and in many cases improves cell permeability by masking polar backbone amides. Staple positions must be chosen with care: residues on the same helical face, separated by one to four positions depending on bridge length, are the typical candidates. Our stapled peptide synthesis capability supports pilot peptides at i, i+3, i+4, and i+7 spacings, with bridge length optimized for the chosen scaffold, and we can incorporate fluorescent or affinity tags alongside the staple to support downstream binding and uptake assays.

Supported applications: stapled libraries are essential for targeting intracellular protein-protein interactions, where the target binding surface is large and flat and a defined helical geometry is the only realistic way to engage it with a peptide-sized molecule. Because the staple improves both stability and cellular uptake, these libraries are the standard format for transcription-factor and apoptotic-pathway targets, for helical peptide leads that must survive in protease-rich environments, and for structure-guided campaigns where a known helical epitope needs to be locked into its bioactive conformation.

Macrocyclic Peptide Libraries (lactam, triazole, thioether bridges)

Design logic and features: macrocyclic libraries extend the constraint concept to larger rings and a choice of cyclization chemistries — lactam bridges between side-chain amines and carboxyl groups, copper-catalyzed azide-alkyne cycloaddition (CuAAC) triazole closures, and thioether linkages from cysteine–chloroacetyl reactions. Each bridge type brings a different combination of ring-size tolerance, metabolic stability, and synthetic accessibility, and our chemists select the chemistry that best fits the design intent rather than defaulting to a single approach. The resulting peptides occupy a chemical space between classical cyclic peptides and small molecules, with molecular weights typically in the 700 to 1500 Da range, conformations biased toward defined structures, and properties (permeability, stability, oral bioavailability) that are tunable through the choice of cyclization chemistry. Mixed architectures — for example, a lactam bridge combined with a stapled helical stretch — are supported when a single constraint does not give enough structural definition.

Supported applications: macrocyclic libraries are particularly valuable when the screening target is a hot spot on a difficult protein-protein interaction, an enzyme site with conformational restriction requirements, or a target where linear peptides have already failed in permeability or stability. Our macrocyclic peptide synthesis team works with the client's design intent to select cyclization chemistries, ring sizes, and bridge placements that give the library the structural diversity needed to test the target hypothesis, and the same libraries feed directly into permeability and stability cascades that rank the resulting hits.

Table.4 Cyclic and Constrained Peptide Library Offerings.

Modified, Labeled, and Branched Peptide Libraries

Many of the most informative libraries in modern peptide research are not defined by their sequence alone but by chemical features installed during synthesis: post-translational modifications, affinity or fluorescent tags, and branched architectures that present multiple copies of an epitope at once. Modified, labeled, and branched libraries extend the screening question beyond "which sequence binds?" to "which modified sequence, captured in which format, gives the strongest and most interpretable signal?". They are essential for antibody work, PTM biology, capture-and-pull-down studies, and any application where a label or topology change is part of the experimental design.

Post-Translational Modification Peptide Libraries (phospho, acetyl, methyl, glyco, ubiquitin remnants)

Design logic and features: PTM libraries install biologically relevant modifications directly into peptides during synthesis, using protected building blocks that survive Fmoc deprotection and global cleavage. The libraries cover the full range of common PTM chemistries — phosphoserine, phosphothreonine, and phosphotyrosine for phosphorylation; acetyl-lysine for acetylation; mono-, di-, and tri-methyl lysine and arginine analogues for methylation; serine/threonine O-glycan and asparagine N-glycan building blocks for glycosylation; and lysine-linked ubiquitin remnant analogues for ubiquitination studies. Each modification is installed at the residue position specified by the researcher, with matched unmodified controls included on request so that every screen can resolve the contribution of the modification itself from the contribution of the surrounding sequence. Because some modifications are sensitive to acidic or basic conditions encountered during cleavage or assay exposure, installation is coupled with stability verification under the storage and assay conditions the library will encounter.

Supported applications: PTM libraries are the reagents of choice for PTM-specific antibody generation and validation, reader-domain and effector binding studies, kinase and phosphatase substrate profiling, and the dissection of how a single modification changes recognition by antibodies, domains, or enzymes. Modified peptide synthesis at BOC Sciences includes the analytical package required to verify both identity and modification state for every member, with optional MS/MS fragmentation patterns that confirm site-specific installation.

Biotinylated, Fluorescent, and Labeled Peptide Libraries (N-/C-terminal tags, dye and linker options)

Design logic and features: labeled libraries carry affinity tags, fluorophores, or reactive handles that allow the peptides to be captured, detected, or conjugated during the screening workflow. Standard installations include N-terminal or C-terminal biotin (with optional PEG linker length), N-terminal or lysine-side-chain fluorescent labels (FITC, FAM, TAMRA, and related dyes), and C-terminal or internal cysteine/amine reactive handles for site-specific conjugation. The position of the label is as important as the label itself: a biotin on the N-terminus of an antibody epitope peptide may mask the very stretch the library is trying to map, while the same biotin placed on a flexible PEG linker at the C-terminus leaves the epitope fully exposed. Our chemists help choose label position, linker chemistry, and dye compatibility with the screening format.

Supported applications: these libraries serve streptavidin-capture assays, fluorescence polarization and FRET measurements, flow cytometry binding studies, pull-down experiments, and conjugation to carriers or beads, and they pair naturally with epitope mapping and SAR libraries where the same set of sequences needs to be screened in a detection format. We also support peptide conjugation service workflows that go beyond standard terminal labels — dye-quencher FRET pairs, click-chemistry handles for late-stage diversification, and lipid or sterol conjugation for membrane interaction studies.

Branched and MAP Peptide Libraries (2-, 4-, 8-arm lysine cores)

Design logic and features: branched libraries, including multiple antigenic peptide (MAP) constructs, present multiple copies of a peptide epitope on a branched lysine core. We support the standard 2-arm (divalent), 4-arm (tetravalent), and 8-arm (octavalent) MAP architectures, with all branches carrying the same epitope or split between two epitopes for dual-purpose immunization. Because every additional branch multiplies the synthesis effort and the QC burden, architectural planning matters: common formats include four-branched and eight-branched cores, and custom architectures (mixed-branch lengths, non-lysine scaffolds, asymmetric arm composition) are available for unusual display requirements. Our branched peptide synthesis platform supports all of these configurations with analytical verification of each arm.

Supported applications: the branched format produces a high-epitope-density immunogen or screening reagent that does not require an external carrier protein and avoids the risk of carrier-induced epitope masking. MAP libraries are used for antibody generation, immune monitoring, and any assay where presenting multiple copies of an epitope increases signal strength — for example, solid-phase binding assays where monovalent peptides give weak or ambiguous readouts. The same architectures serve as potent screening probes when a multivalent display better mimics the natural density of the target interaction.

Table.5 Modified, Labeled, and Branched Peptide Library Offerings.

Application-Focused Peptide Libraries

Application-focused peptide libraries are configured around a defined research domain rather than around a general library architecture. The chemistry is the same as for any other custom library, but the design intent, sequence choices, and quality criteria are tuned to the specific use case. Antimicrobial, cosmetic, and antigen libraries are three of the most active categories in peptide research, and each combines a defined scientific goal with library formats that have been refined across many prior programs.

Antimicrobial Peptide Libraries (cationic, amphipathic, 12–50 mers)

Design logic and features: antimicrobial peptide (AMP) libraries explore cationic, amphipathic sequences that interact with bacterial and fungal membranes. Standard library members span 12 to 50 residues, are enriched in arginine, lysine, and tryptophan, and frequently incorporate disulfide bridges or other constraints to lock the membrane-active conformation in place. Our AMP library formats include positional scans of a lead cationic sequence, alanine walks through the hydrophobic face, and combinatorial libraries of charge-and-hydrophobicity-defined peptides, with matched membrane-active and membrane-inactive controls so that the biophysical readout can be attributed to amphipathicity rather than to overall hydrophobicity. Counter-ion and storage format are treated as first-class design parameters — acetate rather than TFA is often selected for cell-based assays, and DMSO stocks versus lyophilized powder are chosen against the screening cascade.

Supported applications: these libraries feed broth-microdilution MIC workflows, hemolysis counterscreens, time-kill kinetics, and resistance-frequency studies, where the same peptide preparation can perform very differently across assay types and the preparation choices made at design time determine whether the downstream data are comparable. They are used to map the amphipathic requirements of a lead AMP, to improve selectivity between bacterial and mammalian membranes, and to explore constrained scaffolds that preserve membrane activity while gaining proteolytic stability.

Cosmetic Peptide Libraries (signal, carrier, neurotransmitter-inhibiting sequences)

Design logic and features: cosmetic peptide libraries explore three defined functional classes — signal peptides (matrikines that stimulate collagen, elastin, or hyaluronic acid synthesis), carrier peptides (copper-binding and metal-ion transport motifs), and neurotransmitter-inhibiting peptides (expression-line softening and muscle-relaxation analogues). The library is built on well-characterized scaffolds such as GHK, copper-binding tripeptides, palmitoyl pentapeptides, and hexapeptide derivatives, with substitution and truncation variants arranged around each scaffold so that the structure-activity relationship of cosmetic activity can be mapped in the same way as a pharmaceutical SAR program. Because a cosmetic peptide must often survive incorporation into aqueous gels, emulsions, and serums, purity expectations, counter-ion, residual solvent profile, and salt form are treated as first-class design parameters rather than afterthoughts.

Supported applications: cosmetic library programs are typically structured as a focused batch of 10 to 50 peptides exploring variants of a known cosmetic peptide scaffold, with iterations based on in vitro fibroblast, keratinocyte, or enzymatic assays. They support the mapping of matrikine activity, optimization of metal-ion delivery motifs, and refinement of expression-line softening analogues, with formulation-compatibility testing guiding which variants advance.

Peptide Antigen Libraries for Vaccine and Immune Monitoring Research (15–25 mers, HLA-tailored)

Design logic and features: peptide antigen libraries are designed as chemically defined immunogens and monitoring reagents, each member representing a defined stretch of a target protein. Our standard antibody-oriented libraries use 15–25 mers chosen for surface accessibility and minimal internal cross-reactivity, while T-cell-oriented libraries use 8 to 15 residues to match MHC class I or class II presentation, with optional coverage of HLA-class-II-promiscuous or HLA-tailored anchor residues. For high-titre antibody work, peptide antigens are typically conjugated to a carrier protein such as KLH or BSA, or assembled into MAP constructs; for T-cell work, peptides are often delivered as matrix pools that allow deconvolution of the immune response across an entire protein. Synthesis is planned to avoid post-translational or chemical modifications on residues that are part of the epitope, and production conditions minimize side reactions.

Supported applications: antigen libraries support antibody generation, T-cell epitope mapping, and immune monitoring campaigns, and they are the standard reagents for ELISpot and intracellular cytokine staining workflows. Peptide antigen synthesis demands high purity because contaminants from synthesis can dominate the antibody response and obscure the intended epitope, so each peptide is characterized by HPLC and MS and is accompanied by detailed documentation that supports rigorous characterization of the immunogen.

Table.6 Application-Focused Peptide Library Use Cases.

BOC Sciences Custom Peptide Library Solutions

BOC Sciences operates a dedicated custom peptide library synthesis capability within our broader peptide services platform, supporting academic, biotechnology, and pharmaceutical researchers from design through delivery. Our peptide chemists treat each library as a defined scientific project rather than a list of products, beginning with a design consultation, scaling up through a representative pilot when needed, and completing the engagement with the analytical package and documentation the screening workflow requires. Whether the goal is an eight-peptide alanine scan, a 96-well positional scanning library, or a 1,000-member overlapping library across an entire proteome, the engagement is structured around the research question rather than a generic catalog offer.

End-to-End Library Design and Synthesis Workflow

Every custom peptide library project follows the same end-to-end workflow, with the depth of each step matched to the library's complexity and the program's screening strategy, and the process is built to surface design risks early — before synthesis is committed — so that the library delivered to the bench is the library the researcher designed.

Design consultation: a short consultation to align the library with the screening goal, including choice of library type, length window, variable positions, modification scope, and analytical requirements.

Sequence review and feasibility: each member sequence is checked for synthesis risk (hydrophobic stretches, aggregation-prone motifs, oxidation-sensitive residues) and modified if biology allows, with the design note returned for client review.

Representative pilot: when the library introduces new modifications, new constraints, or new coupling challenges, a pilot peptide is synthesized first to confirm yield, purity, and modification state.

Parallel synthesis: library members are synthesized in parallel under conditions tuned to the sequence class, with difficult sequences receiving double couplings, extended deprotection, or alternative solvent systems.

Cleavage, purification, and formatting: peptides are cleaved under conditions that protect modifications, purified to the agreed tier, and reformatted into the requested delivery configuration.

Quality Control, Purification, and Delivery Formats

Quality control is built into every step rather than bolted on at the end. Each library member is verified by analytical HPLC for purity and by mass spectrometry for identity, and the analytical package returned with the library is consistent with the screening tier the researcher has chosen; higher-tier libraries add HRMS confirmation, amino acid analysis, or sequence MS/MS, and pooled libraries are supported by representative-member characterization that documents the integrity of the pool before it is shipped. Delivery formats are matched to the screening workflow: standard delivery is small-scale lyophilized peptides in 96-well plates or individual microtubes with TFA as the default counter-ion; cell-based assays can request acetate or chloride counter-ions to avoid TFA-associated cytotoxicity; and HPLC-purified peptides can be delivered in DMSO solution for direct transfer to screening plates. Plate maps and sequence files accompany every library so that automated screening workflows can integrate the library without manual reformatting.

Service Portfolio for Custom Peptide Libraries

The custom peptide library portfolio at BOC Sciences covers the full range of library formats described in this article, alongside the supporting analytical and conjugation services that peptide programs frequently require. Researchers can engage on a single library, on a recurring library supply agreement, or on a fully integrated peptide discovery program that combines library design, screening support, and follow-up analogue synthesis.

Table.7 Custom Peptide Library Services at BOC Sciences.

Expert Services Supporting Biomolecule Synthesis

Expert Services Supporting Screening Libraries