Peptides are short chains of amino acids linked by peptide bonds, typically consisting of 2 to 50 amino acids. They are structurally smaller than proteins, often referred to as small or mini proteins. Peptides play diverse and essential roles in biological systems, functioning as hormones, neurotransmitters, antimicrobial agents, signaling molecules, and enzyme regulators, etc. Their ability to interact specifically with biological targets makes them invaluable in medicine, biotechnology, and industrial applications. As a result, peptides are widely used as therapeutics, cosmetics, and research tools.
The discovery and development of novel peptides for these applications require efficient screening methods. One of the most powerful strategies is the use of peptide libraries. A peptide library is a collection of diverse peptides designed for high-throughput screening in biochemical and pharmaceutical research. These libraries are instrumental in studying protein-protein interactions, enzyme-substrate specificity, drug discovery, and epitope mapping. By systematically varying peptide sequences and structures, researchers can identify bioactive peptides with desirable properties for therapeutic and industrial applications.
Peptide libraries can be broadly categorized into two types:
Synthetic Peptide Libraries
Created using solid-phase peptide synthesis (SPPS), these libraries allow for precise control over peptide sequences. They can be designed randomly or based on specific structures of interest, making them a versatile tool for screening and optimization.
Biological Peptide Libraries
These libraries are generated using techniques such as phage display or ribosome display, where peptides are either expressed on the surface of bacteriophages or linked to their encoding mRNA. These libraries often contain billions to trillions of peptide variants, forming “super mixtures” that significantly enhance the chances of identifying potent bioactive peptides.
Current global peptide libraries face several critical challenges, including:
Limited Structural Diversity
Most libraries consist of only a single type of peptide structure, reducing the scope of potential discoveries.
Low Sequence Diversity
A restricted range of sequences limits the ability to identify novel bioactive peptides.
Complex Mixture-Based Libraries
Super mixture-based libraries contain hundreds of millions of peptides in highly complex pools, making it difficult to efficiently capture high-quality active peptides.
PeptiOrigin's innovative 3D-Structured Peptide Library offers unparalleled features and is designed to address these challenges, including:
Trillion-level peptide sequence diversity enabling vast exploration of bioactive candidates.
Inclusion of all five major peptide structures significantly expanding structural diversity.
A non-super mixture design ensuring high screening success rates and faster active peptide discovery.
Versatility across all targets and screening models making it suitable for various research and therapeutic applications.
By leveraging PeptiOrigin’s peptide library, researchers can accelerate the development of innovative peptide-based therapeutics and biomolecules, driving progress in drug discovery.
Sequence Diversity
Principles of Our Big Data-Driven Peptide Sequence Design
Incorporates non-natural amino acids for superior peptide properties.
Our peptide library is designed with unparalleled sequence diversity, enabling the discovery of high-affinity, functionally optimized peptide candidates for drug development, biomarker discovery, and targeted therapies.
Structure Diversity
Bioactive peptides display both sequence and structural diversity, meaning that their amino acid composition and three-dimensional conformation collectively influence their biological activities. Examples include linear peptides like glutathione and aspartame, cyclic peptides like octreotide, and more complex structures such as vancomycin and ziconotide with three rings. These structural variations are key to their bioactivity.
Structural variations in peptides significantly impact their physicochemical properties, such as solubility, permeability, lipophilicity, and total polar surface area. Moreover, these variations greatly influence the binding capacity, functional activity, or selectivity of peptides toward their targets.
Currently, most peptide libraries on the market feature only one type of structure—either linear, cyclic, or bicyclic. While these libraries have facilitated the discovery of some bioactive peptides, their limited structural diversity significantly constrains the potentials for discovering new bioactive molecules.
Our library includes peptides with diverse 3D structures: linear, cyclic, bicyclic, tricyclic, and tetracyclic structures, along with over 10 novel structures not found in nature. These innovations enhance binding affinity, specificity, stability, and even oral availability, making the library ideal for drug discovery.
Linear
Leuprolide
Teriparatide
Semaglutide
Cyclic
Octreotide
Oxytocin
Mixed
Vasopressin
Daptomycin
Insulin
Bicyclic
Endothelin
Vancomycin
Tricyclic
Ziconotide
μ-Conotoxin
Peptides, especially natural ones, form unique 3D structures, which are critical for their bioactivities.
Size Diversity
Size diversity in a peptide library is crucial for several reasons:
Enhanced Coverage of Potential Targets:
Different peptide sizes interact with biological targets in unique ways. Shorter peptides may access shallow binding pockets, while longer peptides can interact with larger or more complex surfaces. Size diversity ensures that a broader range of potential targets is addressed.
Maximized Functional Diversity:
Peptide size affects structural and functional diversity. Shorter peptides are simpler and may mimic small molecular motifs, while longer peptides can adopt complex secondary and tertiary structures, offering varied biological activities.
Minimized Development Risks:
Size diversity allows researchers to identify candidates with the best balance of efficacy, stability, and manufacturability, reducing the risk of failure during development.
Minimized Immunogenicity:
Peptide size plays a crucial role in immunogenicity, which should be minimized for drug development. Larger peptides, particularly those exceeding 12–15 amino acids, are more likely to trigger an immune response. Therefore, controlling peptide size is essential to reducing immunogenicity risks.
Improved Screening Efficiency:
Including peptides of various lengths increases the likelihood of discovering peptides with optimal properties for a specific target, such as binding affinity, specificity, or stability.
Short peptides offer the benefits of low manufacturing costs and minimal to no immunogenicity, making them ideal for long-term use as new drugs. Our library includes peptides ranging from 2 to 20 amino acids, providing a diverse range of options.
2 aa: 202 = 400
3 aa: 203 = 8,000
4 aa: 204 = 160,000
5 aa: 205 = 3,200,000
6 aa: 206 = 64,000,000
Our library contains:
All Dipeptides
All Tripeptides
All Tetrapeptides
All Pentapeptides
All Hexapeptides
Peptides ranging from 7 to 20 amino acids in length designed to maximize sequence diversity through the application of mathematical principles.
Non-Super Mixture Library
Existing combinatorial chemistry and phage display libraries are known for their large capacity (trillions) and high screening efficiency, enabling trillions of peptides to be screened in a single round. However, these libraries have notable limitations despite their wide use.
Super mixture of billion or trillion peptides
Drawbacks:
Extremely low peptide concentration reduces the likelihood of identifying optimal candidates.
Significant and unavoidable peptide interactions can lead to false positives and false negatives.
Limited structural diversity in libraries restricts the discovery of novel bioactive peptides.
Complex peptide mixtures in libraries can hinder efficient and accurate screening, making them unsuitable for certain methods, such as phenotype or cell-based screening.
Our non-super mixture library contains 200,000 small peptide library with each containing 1 to thousands different peptides, which significantly reduces the false positive rates and false negative rates, leading to higher screening success and faster discovery of active peptides. The library is also suitable for any screening models or methods such as phenotype screening or cell-based assays.
Fluorescein-Labeled Peptides
Peptides such as cell-penetrating peptides, targeted cell-penetrating peptides, and transdermal peptides often contain a higher proportion of basic amino acids like arginine and lysine. These peptides carry a positive charge in the human body, enabling them to bind with negatively charged phosphate groups on cell membranes—a key condition for crossing the membrane.
Additionally, amino acids like tyrosine, tryptophan, and phenylalanine significantly contribute to membrane penetration, followed by hydrophobic amino acids like leucine and isoleucine. Conversely, acidic amino acids, due to their negative charge, repel the phosphate groups on the membrane, making them less favorable for transmembrane activity.
Based on these principles and the company's expertise in peptide library design, selected peptides in the library are fluorescently labeled to enable efficient screening of cell-penetrating peptides, targeted cell-penetrating peptides, and transdermal peptides.
We leverage our proprietary large-scale peptide library to deliver comprehensivepeptide drug discovery CRO services.
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