Small molecule inhibitor

Macrocyclic compounds (≥12-atom cyclic small molecules/peptides) have unique physicochemical properties. They form preorganized conformations with high binding affinity/selectivity, target traditional small-molecule-inaccessible proteins, and bridge small-molecule drugs and biological agents. As key protein phosphorylation enzymes, kinases are linked to tumors, COPD, etc., and are critical therapeutic targets. Traditional small-molecule kinase inhibitors lack selectivity, causing off-target toxicity, low bioavailability, and acquired resistance. Macrocycles’ semi-rigid structure restricts conformations, boosts binding selectivity, optimizes pharmacokinetics, and makes macrocyclization a core kinase inhibitor optimization strategy.

Thousands of bioactive macrocycles were curated from ChEMBL. Via Transformer, macrocyclization was converted into a chemical language translation task, enabling end-to-end macrocycle generation from linear precursors with simplified inputs. Macformer achieves efficient, automated linear molecule macrocyclization via deep learning; generated macrocycles have diversity, novelty, biocompatibility, and cover broader chemical space.

MCE collected thousands of marketed/clinical kinase inhibitors, using their fragments for macrocyclization to generate derivatives. After evaluating synthetic accessibility and physicochemical properties, a million-scale virtual macrocyclic library was built for kinase-related virtual and AI-driven screening.

Macrocyclic compounds (≥12-atom cyclic small molecules/peptides) have unique physicochemical properties. They form preorganized conformations with high binding affinity/selectivity, target traditional small-molecule-inaccessible proteins, and bridge small-molecule drugs and biological agents. As key protein phosphorylation enzymes, kinases are linked to tumors, COPD, etc., and are critical therapeutic targets. Traditional small-molecule kinase inhibitors lack selectivity, causing off-target toxicity, low bioavailability, and acquired resistance. Macrocycles’ semi-rigid structure restricts conformations, boosts binding selectivity, optimizes pharmacokinetics, and makes macrocyclization a core kinase inhibitor optimization strategy.

Thousands of bioactive macrocycles were curated from ChEMBL. Via Transformer, macrocyclization was converted into a chemical language translation task, enabling end-to-end macrocycle generation from linear precursors with simplified inputs. Macformer achieves efficient, automated linear molecule macrocyclization via deep learning; generated macrocycles have diversity, novelty, biocompatibility, and cover broader chemical space.

MCE collected thousands of marketed/clinical kinase inhibitors, using their fragments for macrocyclization to generate derivatives. After evaluating synthetic accessibility and physicochemical properties, a million-scale virtual macrocyclic library was built for kinase-related virtual and AI-driven screening.

Small molecule covalent inhibitors, or irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity, such that covalent warheads can target rare residues of a particular target protein, thus leading to the development of highly selective inhibitors and achieving a more complete and continued target occupancy in living systems. In recent years, the distinct strengths of covalent inhibitors in overcoming drug resistance had been recognized. However, toxicity can be a real challenge related to this class of therapeutics due to their potential for off-target reactivity and has led to these drugs being disfavored as a drug class. The drug design and optimization of covalent inhibitors has become a hot spot in drug discovery.

MCE covalent inhibitor library contains 1,546 small molecules including identified covalent inhibitors and other bioactive molecules having common covalent reactive groups as warheads, such as acrylamides, activated terminal acetylenes, Sulfonyl fluorides/esters, cloracetamides, alkyl halides, epoxides, aziridines, disulfides, etc.

Small molecule covalent inhibitors, or irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity, such that covalent warheads can target rare residues of a particular target protein, thus leading to the development of highly selective inhibitors and achieving a more complete and continued target occupancy in living systems. In recent years, the distinct strengths of covalent inhibitors in overcoming drug resistance had been recognized. However, toxicity can be a real challenge related to this class of therapeutics due to their potential for off-target reactivity and has led to these drugs being disfavored as a drug class. The drug design and optimization of covalent inhibitors has become a hot spot in drug discovery.

MCE covalent inhibitor library contains 5,994 small molecules including identified covalent inhibitors and other molecules having common covalent reactive groups as warheads, such as acrylamides, activated terminal acetylenes, sulfonyl fluorides/esters, cloracetamides, alkyl halides, epoxides, aziridines, disulfides, etc.

MCE Covalent inhibitor Library plus, with more powerful screening capability, further complement Covalent inhibitor Library (HY-L036) by adding some fragment compounds with covalent warheads.

Kinases is a class of enzymes that adds chemicals called phosphates to other molecules, such as sugars or proteins. Protein phosphorylation serves as a critical regulatory mechanism for numerous cellular processes including cell division, metabolism, and signal transduction, with approximately 50% of cellular functions in humans being regulated by kinase activity. In drug discovery, kinases represent a major category of therapeutic targets, and kinase inhibitors constitute an important class of pharmaceuticals that block the activity of specific disease-associated enzymes, particularly in cancer and inflammatory disorders. Small molecule kinase inhibitors represent one of the fastest-growing drug categories, having received U.S. Food and Drug Administration (FDA) approval for both oncological and non-oncological indications. As of September 2023, over 70 FDA-approved small molecule kinase inhibitors are commercially available.

The MCE Kinase Inhibitor Library Mini contains 270 kinase inhibitors primarily targeting protein kinases (VEGFR, EGFR, BTK, CDK, Akt, etc.), lipid kinases (PI3K, PI4K, SK, etc.), and carbohydrate kinases. This collection includes 1-3 highly specific representative compounds per target, optimized for screening of kinase-related drug targets in pharmaceutical research.

Covalent inhibitors are small molecules that can bind specifically to target proteins through covalent bonds and inhibit their biological functions. Although for a long time, covalent targeting has been playing a subordinate role in drug discovery, with an increasing number of reports on successful clinical applications of such drugs, the potential of these agents is now being acknowledged.

Covalent ligands rely on reactive groups (“warheads”), and new warheads are key to expanding the scope of covalent modalities. Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 8,900 fragment molecules with covalent modification potential, which can target various reactive amino acid residues and can be used for fragment-based covalent drug discovery.

Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. PROTACs consist of a ligand for E3 ligase (E3 ligase binder), a linker and a ligand (mostly small-molecule inhibitor) for protein of interest（target binder）. Upon binding to the target protein, the PROTACs can recruit E3 for target protein ubiquitination, which is subjected to proteasome-mediated degradation.

Although there are more than 600 E3 ubiquitin ligases, only several with small molecule ligands have been used for designing PROTACs, including Skp1-Cullin-F box complex containing Hrt1 (SCF), Von Hippel-Lindau tumor suppressor (VHL), Cereblon (CRBN), inhibitor of apoptosis proteins (IAPs), and mouse double minute 2 homolog (MDM2).

MCE carefully prepared a unique collection of 174 ligands for E3 ligase, which have been reported to be used in PROTAC design. MCE E3 ligase ligand library is a useful tool for PROTAC development.

In this era of rapid advancement in gene-editing technology, the CRISPR-Cas system, with its powerful programmability, is leading a transformation in life sciences research. It enables efficient and precise targeted modification of an organism's genome, providing a robust tool for studying gene function, treating genetic diseases, and improving crop varieties. However, bottlenecks such as insufficient editing efficiency, low homologous directed repair efficiency, and potential off-target risks remain major challenges in achieving precise genetic modifications and developing gene therapies.

To overcome these limitations, the MCE High-Efficiency Gene Editing Compound Library systematically includes 730 small molecules that are known or have the potential to enhance gene-editing efficiency. These compounds work by targeting and modulating the DNA damage repair network, mechanistically inhibiting non-homologous end joining, promoting homologous directed repair, or regulating chromatin states and cellular responses, thereby significantly optimizing editing outcomes. This library is suitable for developing "CRISPR-small molecule" combination therapy strategies, improving gene-editing efficiency, and providing a powerful tool for in-depth research into the mechanisms of DNA damage repair in gene editing.

A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. Proteases play important roles in regulating multiple biological processes in all living organisms, such as regulating the fate, localization, and activity of many proteins, modulating protein-protein interactions, creating new bioactive molecules, contributing to the processing of cellular information, and generating, transducing, and amplifying molecular signals.

Proteases are important targets in drug discovery. Some protease inhibitors are often used as anti-virus drugs and anti-cancer drugs. MCE offers a unique collection of 927 protease inhibitors. MCE Protease Inhibitor Library is critical for drug discovery and development.

Exosomes are small membrane vesicles of endocytic origin that are secreted by most cells in culture. Exosomes contain nucleic acids, proteins, lipids, amino acids, and metabolites, etc. Their diverse constituents can reflect their cell of origin. Exosomes are associated with immune responses, viral pathogenicity, pregnancy, cardiovascular diseases, central nervous system-related diseases, and cancer progression. Proteins, metabolites, and nucleic acids delivered by exosomes into recipient cells effectively alter their biological response. Such exosome-mediated responses can be disease promoting or restraining.

The biology of exosomes in disease is still emerging, and the number of studies addressing their utility in the diagnosis and treatment of various pathologies has increased substantially. MCE supplies a unique collection of 53 compounds with the activity of inhibiting or stimulating exsomes secretion/biosynthesis. MCE Exosomes Compound Library is a useful tool for exsomes research.

The developmental proteins Hedgehog, Notch and Wnt are key regulators of cell fate, proliferation, migration and differentiation in several tissues. Their related signaling pathways are frequently activated in tumors, and particularly in the rare subpopulation of cancer stem cells. The Wnt signaling pathway is a conserved pathway in animals. Deregulated Wnt signaling has catastrophic consequences for the developing embryo and it is now well appreciated that defective Wnt signaling is a causative factor for a number of pleiotropic human pathologies, including cancer. Hedgehog signaling pathway is linked to tumorigenesis and is aberrantly activated in a variety of cancers. The Notch signaling pathway is a highly conserved cell signaling system present in most animals. It plays an important role in cell-cell communication, and further regulates embryonic development.

MCE designs a unique collection of 601 Wnt/Hedgehog/Notch signaling pathway-related small molecules. Wnt/Hedgehog/Notch Compound Library serves as a useful tool for stem cell research and anti-cancer drug screening.

The rising prevalence of multidrug-resistant and extensively drug-resistant bacteria, combined with emerging resistance mechanisms and the limitations of existing antibacterial drugs, creates an urgent need for novel antibacterial agents. Antibacterial compound libraries serve as key tools to support antibacterial drug screening and development.

This library features structurally diverse compounds, including small-molecule scaffolds and natural product derivatives, and exhibits diverse antibacterial mechanisms of action. For example, these compounds exert antibacterial effects by disrupting bacterial cell structures, interfering with bacterial metabolic processes, and inhibiting nucleic acid synthesis. The derivation of scaffold structures enhances their activity against drug-resistant bacteria and their selectivity against different types of bacteria. This library can be used for the high-throughput screening of novel antibacterial drug candidates and the identification of potent compounds against drug-resistant and multidrug-resistant bacteria. Additionally, it provides a reference for compound structural modification, enabling further in-depth research on the structure-activity relationships(SARs) of antibacterial drugs. It can also be applied to the exploration of bacterial resistance mechanisms and reversal strategies, as well as the discovery of antibacterial molecules that inhibit efflux pumps and restore drug susceptibility.

The library contains 10855 structurally diverse drug-like compounds. Its core compound sources include analogs of known antifungal active moleculeswith a similarity score of ≥ 0.6. MCE has collected more than 1900 antibacterial molecules. All screened compounds conform to lead-like physicochemical properties, providing valuable support for the research and development of novel antibacterial drugs.

Neurotransmitter (NT) receptors, also known as neuroreceptors, are a broadly diverse group of membrane proteins that bind neurotransmitters for neuronal signaling. There are two major types of neurotransmitter receptors: ionotropic and metabotropic. Ionotropic receptors are ligand-gated ion channels, meaning that the receptor protein includes both a neurotransmitter binding site and an ion channel. The binding of a neurotransmitter molecule (the ligand) to the binding site induces a conformational change in the receptor structure, which opens, or gates, the ion channel. The term “metabotropic receptors” is typically used to refer to transmembrane G-protein-coupled receptors. Metabotropic receptors trigger second messenger-mediated effects within cells after neurotransmitter binding.

In some neurological diseases, the neurotransmitter receptor itself appears to be the target of the disease process. Many neuroactive drugs act by modifying neurotransmitter receptors. A better understanding of neurotransmitter receptor changes in disease may lead to improvements in therapy.

MCE designs a unique collection of 2,495 compounds targeting a variety of neurotransmitter receptors. MCE Neurotransmitter Receptor Compound Library is a useful tool for neurological diseases drug discovery.

Covalent inhibitors are small molecules that can bind specifically to target proteins through covalent bonds and inhibit their biological functions. Although for a long time, covalent targeting has been playing a subordinate role in drug discovery, with an increasing number of reports on successful clinical applications of such drugs, the potential of these agents is now being acknowledged. Currently, cysteine is the most common covalent amino acid residue in a variety of covalent drugs, and various warheads have been developed that can react with cysteine, providing the key building blocks for covalent drugs to form covalent bonds.

To meet the development needs of covalent inhibitors targeting cysteine, MCE has designed a unique collection of 5,112 compounds with different covalent warheads that target cysteine. The MCE Cysteine Targeted Covalent Library is designed using the following covalent warheads: Acrylamides, Propiolic acid ester, Dimethylamine functionalized acrylamides, Chloroacetamides, Acrylonitrile, 2-Cyanoacrylamide, Aziridine, Haloacetamide, etc.

Adult stem cells are important for tissue homeostasis and regeneration due to their ability to self-renew and generate multiple types of differentiated daughters. Self-renewal is reflected by their capacity to undergo multiple/limitless divisions. Several signaling pathways are involved in self-renewal of stem cells, that is, Notch, Wnt, and Hedgehog pathways or Polycomb family proteins. Recent studies mainly focus on cancer stem cell (CSCs), induced pluripotent stem cell (iPSCs), neural stem cell and maintenance of embryonic stem cell pluripotency. Among them, CSCs have been believed to be responsible for tumor initiation, growth, and recurrence that have implications for cancer therapy.

MCE owns a unique collection of 2,723 compounds that can be used for stem cell regulatory and signaling pathway research.

The PI3K/Akt/mTOR pathway controls many cellular processes that are important for the formation and progression of cancer, including apoptosis, transcription, translation, metabolism, angiogenesis, and cell cycle progression. Every major node of this signaling network is activated in a wide range of human tumors. Mechanisms for the pathway activation include activation of receptor tyrosine kinases (RTKs) upstream of PI3K, mutation or amplification of PIK3CA encoding p110α catalytic subunit of PI3K, mutation or loss of PTEN tumor suppressor gene, and mutation or amplification of Akt1. Once the pathway is activated, signaling through Akt can stimulate a series of substrates including mTOR which is involved in protein synthesis. Thus, inhibition of this pathway is an attractive concept for cancer prevention and/or therapy. Currently some mTOR inhibitors are approved for several indications, and there are several novel PI3K/Akt/mTOR inhibitors in clinical trials.

MCE owns a unique collection of 1,049 compounds that can be used for PI3K/Akt/mTOR pathway research. PI3K/Akt/mTOR Compound Library also acts as a useful tool for anti-cancer drug discovery.

Endoplasmic reticulum (ER) contributes to the production and folding of approximately one third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. However, some adverse factors negatively impact ER functions and protein synthesis, resulting in the activation of Endoplasmic reticulum stress (ER stress, ERS) and unfolded protein response (UPR) signaling pathways. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. Chronic ER stress and defects in UPR signaling are emerging as key contributors to a growing list of human diseases, including diabetes, neurodegeneration and cancer.

MCE Endoplasmic Reticulum Stress Compound Library contains 356 ER stress-related compounds that mainly target PERK, IRE1, ATF6, etc. MCE ER stress library is a useful tool for researching ER stress and related diseases.

Small molecule covalent inhibitors, or irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity, such that covalent warheads can target rare residues of a particular target protein, thus leading to the development of highly selective inhibitors and achieving a more complete and continued target occupancy in living systems. In recent years, the distinct strengths of covalent inhibitors in overcoming drug resistance had been recognized. However, toxicity can be a real challenge related to this class of therapeutics due to their potential for off-target reactivity and has led to these drugs being disfavored as a drug class. The drug design and optimization of covalent inhibitors has become a hot spot in drug discovery.

MCE Lead-like Covalent Screening Library offers a valuable resource of 1,049 lead-like compounds with commonly used covalent warheads. These warheads, such as acrylamide, activated terminal alkyne, acyloxymethyl ketone, and boronic acid, are capable of reacting with specific amino acid residues, including cysteine, lysine, serine, and histidine. The inclusion of these reactive warheads in the library allows researchers to explore the potential of covalent inhibition, a powerful approach in drug discovery.

DEL technology enables the simultaneous screening of millions or billions of compounds in a single tube by covalently linking each small molecule with a unique DNA sequence. Traditional DEL screening primarily focuses on identifying non-covalent binding molecules, where interactions with the target are reversible. In contrast, DNA‑encoded covalent library is an ultra‑high‑throughput screening library developed on the basis of conventional DNA‑encoded library technology. It incorporates controllable electrophilic covalent warheads capable of forming irreversible covalent bonds with amino acid residues at the active sites of target proteins, including Cys, Lys, Ser, Tyr, and others. This covalent binding enhances binding affinity, prolongs residence time at the target site, and has the potential to overcome challenges associated with traditional non-covalent inhibitors, such as drug resistance or off-target effects.

Each compound in the library contains both a binding domain and an electrophilic warhead. It first recognizes and binds to the target through non covalent interactions, and then forms a stable covalent bond with key amino acid residues to achieve irreversible inhibition. This library is specifically designed for the discovery of potent, long lasting, and highly selective covalent inhibitors, particularly for undruggable targets such as kinases, GPCRs, proteases, and mutant oncoproteins. Each molecule is uniquely labeled with a DNA barcode for molecular identification and sequencing decoding.

This library is an advanced and highly diverse collection, consists of 35 independent sub-libraries with a total scaleof 14 million compounds, It incorporates over 14 experimentally validated covalent warheads capable of targeting cysteine, lysine, arginine, aspartic acid and glutamic acid. This library is constructed with diverse drug like core scaffolds and integrated controllable covalent warheads, it features structural diversity, reaction spec

Mutations in oncogenes and tumor suppressor genes can modify multiple signaling pathways and in turn cell metabolism, which facilitates tumorigenesis. The paramount hallmark of tumor metabolism is “aerobic glycolysis” or the Warburg effect, coined by Otto Warburg in 1926, in which cancer cells produce most of energy from glycolysis pathway regardless of whether in aerobic or anaerobic condition. Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside. The increased uptake of glucose is facilitated by the overexpression of several isoforms of membrane glucose transporters (GLUTs). Likewise, the metabolic pathways of glutamine, amino acid and fat metabolism are also altered. Recent trends in anti-cancer drug discovery suggests that targeting the altered metabolic pathways of cancer cells result in energy crisis inside the cancer cells and can selectively inhibit cancer cell proliferation by delaying or suppressing tumor growth.

MCE provides a unique collection of 3,552 compounds which cover various tumor metabolism-related signaling pathways. These compounds can be used for anti-cancer metabolism targets identification, validation as well anti-cancer drug discovery.

Glutamine is an important metabolic fuel that helps rapidly proliferating cells meet the increased demand for ATP, biosynthetic precursors, and reducing agents. Glutamine Metabolism pathway involves the initial deamination of glutamine by glutaminase(GLS), yielding glutamate and ammonia. Glutamate is converted to the TCA cycle intermediate α-ketoglutarate (α-KG) by either glutamate dehydrogenase (GDH) or by the alanine or aspartate transaminases (TAs), to produce both ATP and anabolic carbons for the synthesis of amino acids, nucleotides and lipids. During periods of hypoxia or mitochondrial dysfunction, α-KG can be converted to citrate in a reductive carboxylation reaction catalyzed by IDH2. The newly formed citrate exits the mitochondria where it is used to synthesize fatty acids and amino acids and produce the reducing agent, NADPH.

Cancer cells display an altered metabolic circuitry that is directly regulated by oncogenic mutations and loss of tumor suppressors. Mounting evidence indicates that altered glutamine metabolism in cancer cells has critical roles in supporting macromolecule biosynthesis, regulating signaling pathways, and maintaining redox homeostasis, all of which contribute to cancer cell proliferation and survival. Thus, intervention in glutamine metabolic processes could provide novel approaches to improve cancer treatment.

MCE owns a unique collection of 1,690 compounds targeting the mainly proteins and enzymes involved in glutamine metabolism pathway. Glutamine Metabolism compound library is a useful tool for intervention in glutamine metabolic processes.

Glycolysis is a series of metabolic processes by which one molecule of glucose is catabolized to two molecules of pyruvate with a net gain of two ATP. Glycolysis takes place in 10 steps and catalyzed by a series of enzyme, such as hexokinase, Glucose-6-phosphate isomerase, Phosphofructokinase, etc. Glycolysis is used by all cells in the body for energy generation.

Most cancer cells exhibit increased glycolysis and use this metabolic pathway for generation of ATP as a main source of their energy supply. This phenomenon is known as the Warburg effect and is considered as one of the most fundamental metabolic alterations during malignant transformation. Because increased aerobic glycolysis is commonly seen in a wide spectrum of human cancers, development of novel glycolytic inhibitors as a new class of anticancer agents is likely to have broad therapeutic applications.

MCE provides a unique collection of 1,258 glycolysis compounds that mainly target hexokinase, glucokinase, enolase, pyruvate kinase, PDHK, etc. MCE Glycolysis Compound Library is a useful tool for glucose metabolism research and anti-cancer drug discovery.

Metabolism is the set of life-sustaining chemical reactions in organisms. Metabolic pathways are enzyme-mediated biochemical reactions that lead to biosynthesis (anabolism) or breakdown (catabolism) of natural product small molecules within a cell or tissue. Acting as catalysts, enzymes are crucial to metabolism - they allow a reaction to proceed more rapidly - and they also allow the regulation of the rate of a metabolic reaction. Proteases are used throughout an organism for various metabolic processes. Proteases control a great variety of physiological processes that are critical for life, including the immune response, cell cycle, cell death, wound healing, food digestion, and protein and organelle recycling. Imbalances in metabolic activities have been found to be critical in a number of pathologies, such as cardiovascular diseases, inflammation, cancer, and neurodegenerative diseases.

MCE designs a unique collection of 7,056 Metabolism/Protease-related small molecules that act as a useful tool for drug discovery of metabolism-related diseases.

Most of molecules enter or leave cells mainly via membrane transport proteins, which play important roles in several cellular functions, including cell metabolism, ion homeostasis, signal transduction, the recognition process in the immune system, energy transduction, etc. There are three major types of transport proteins, ATP-powered pumps, channel proteins and transporters. Transport proteins such as channels and transporters play important roles in the maintenance of intracellular homeostasis, and mutations in these transport protein genes have been identified in the pathogenesis of a number of hereditary diseases. In the central nervous system, ion channels have been linked to, but not limited to, many diseases such asataxias, paralyses, epilepsies, and deafness. This indicates the roles of ion channels in the initiation and coordination of movement, sensory perception, and encoding and processing of information. Ion channels are a major class of drug targets in drug development.

MCE designs a unique collection of 2,174 smal-molecule modulators that can be used for the research of Ion Channel and Membrane Transporter or high throughput screening (HTS) related drug discovery.

Owing to the widespread transmission and frequent mutation of viral diseases, as well as the continuous emergence of new viruses and drug-resistant strains, antiviral drug development is facing increasingly stringent requirements. Antiviral compound libraries serve as important tools for drug screening, mechanism research and development, enabling the discovery and investigation of various antiviral drugs.

These compounds act through diverse antiviral mechanisms, targeting key steps in viral replication, assembly and invasion. They exert antiviral effects by inhibiting viral nucleic acid synthesis, blocking viral protein processing, and preventing viral binding to host cells. This library covers various types of antiviral compounds, including nucleosides, non-nucleosides, protease inhibitors and integrase inhibitors. It supports research on influenza virus, herpes virus, hepatitis virus, emerging respiratory viruses and other pathogens, and enables high-throughput screening of novel antiviral candidates to rapidly identify potential active compounds against diverse viruses. It also facilitates mechanistic studies to elucidate drug-target interactions and viral resistance mechanisms, and supports the screening of effective compounds against mutant strains for research on viral variation and drug resistance.

This antiviral library consists of 6,804 compounds with lead-like physicochemical properties. The core sources of the compounds include analogs of known antiviral molecues with a similarity score ≥ 0.6. MCE has collected more than 1450 antiviral molecules. As a small-molecule collection with both activity potential and structural modifiability, it provides strong support for antiviral drug research and development.

Covalent inhibitors are small molecules that can bind specifically to target proteins through covalent bonds and inhibit their biological functions. Although for a long time, covalent targeting has been playing a subordinate role in drug discovery, with an increasing number of reports on successful clinical applications of such drugs, the potential of these agents is now being acknowledged. Currently, cysteine is the most common covalent amino acid residue in a variety of covalent drugs, and various warheads have been developed that can react with cysteine, providing the key building blocks for covalent drugs to form covalent bonds.

To meet the development needs of covalent inhibitors targeting cysteine, MCE has designed a unique collection of 3,601 fragments with different covalent warheads that target cysteine. The MCE Cysteine Targeted Covalent Fragment Library is designed using the following covalent warheads: Acrylamides, Propiolic acid ester, Dimethylamine functionalized acrylamides, Chloroacetamides, Acrylonitrile, 2-Cyanoacrylamide, Aziridine, Haloacetamide, etc. All fragments are pre-filtered with the Rule of Three restrictions which can be used for fragment-based covalent drug development.

Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. PROTACs consist of a ligand for E3 ligase (E3 ligase binder), a linker and a ligand (mostly small-molecule inhibitor) for protein of interest（target binder）. Upon binding to the target protein, the PROTACs can recruit E3 for target protein ubiquitination, which is subjected to proteasome-mediated degradation. Therefore, PROTACs execute their functions by degrading the target proteins rather than inhibiting them, which has a great superiority in overcoming resistance caused by target mutation or overexpression. To date, PROTAC technology has been applied to a variety of targets, including AR, ER, BTK, BET, and BCR-ABL to overcome resistance.

MCE carefully prepared a unique collection of 94 ligands for target proteins, which have been reported to be used in PROTAC design. MCE Target Protein Ligand Library is a useful tool for PROTAC development.

Nuclear factor-κB (NF-κB)/Rel proteins include NF-κB2 p52/p100, NF-κB1 p50/p105, c-Rel, RelA/p65, and RelB. These proteins function as dimeric transcription factors that regulate the expression of genes and influence a broad range of biological processes including innate and adaptive immunity, inflammation, stress responses, B-cell development, and lymphoid organogenesis. NF-κB plays a key role in regulating the immune response to infection. In addition, activation of the NF-κB pathway is involved in the pathogenesis of chronic inflammatory diseases, such as asthma, rheumatoid arthritis, and inflammatory bowel disease. Incorrect regulation of NF-κB has been linked to cancer, inflammatory and autoimmune diseases, septic shock, viral infection, and improper immune development.

MCE owns a unique collection of 1,670 small molecule compounds that can be used in the research of NF-κB signaling pathway or high throughput screening (HTS) related drug discovery.

Protein lactylation, an emerging post-translational modification identified in recent years, plays a critical role in linking cellular metabolic reprogramming, epigenetic regulation, and signaling networks. Based on a systematic framework encompassing lactate metabolism, lactylation, and downstream signaling pathways, this compound library comprehensively targets multiple regulatory layers, including histone modification enzymes (such as p300 and HDACs), key glycolytic enzymes (such as PKM2, LDHA, and GAPDH), transcriptional regulators (such as STAT3, HMGB1, and p53), as well as central signaling pathway nodes including HIF-1α, NF-κB, and PI3K-AKT-mTOR. This integrated design enables a comprehensive representation of the regulatory roles of lactylation across the “metabolism–epigenetics–signaling” axis.

MCE has assembled a collection of 5,860 known bioactive compounds and potential functional molecules, making this library suitable for a wide range of applications, including high-throughput drug screening, inhibitor identification, and mechanistic studies. It can be used to systematically evaluate the functional roles of lactylation in biological processes such as tumor metabolism, immune regulation, and inflammatory responses, and to efficiently identify small-molecule candidates with regulatory potential, thereby facilitating the development of innovative therapeutics targeting the interplay between metabolism and epigenetic regulation.

The RNA-targeted bioactive compound library is a high-quality collection of small molecules specifically designed and curated to target RNA structures and functions. It is widely applied in cutting-edge drug discovery and life science research. Unlike traditional strategies that focus on protein targets, RNA-targeted compounds can directly modulate various functional RNA molecules by influencing their splicing, translation, stability, or structural conformation, thereby enabling precise intervention in key biological processes. In the field of drug development, these compounds provide a novel approach to addressing previously “undruggable” targets and have demonstrated significant potential in areas such as oncology, antiviral therapies, and neurodegenerative diseases. For example, by targeting disease-associated RNA structural domains or regulating the aberrant expression of non-coding RNAs, these compounds can effectively inhibit disease progression or restore normal cellular function. In mechanistic studies, RNA-targeted compounds serve as valuable chemical biology tools to elucidate the roles of RNA in gene expression regulation, cellular signaling pathways, and disease development.

The MCE RNA-targeted bioactive compound library contains 857 compounds, sourced from databases such as TargetRX Atlas and R-BIND. The library features excellent structural diversity and biological activity, making it suitable for high-throughput screening (HTS), target validation, phenotypic screening, and lead compound discovery. It represents a valuable resource for RNA-related research and innovative drug development.

Immuno-Oncology is a type of immunotherapy that has the specific purpose of treating cancer. It works by stimulating our immune system to fight back. Normally, our immune system is able to destroy cancer cells in our body, however sometimes cancer cells can adapt and mutate, effectively hiding from our immune system. This is when tumors can develop and become a threat to our health. Immuno-oncology involves mobilizing lymphocytes to recognize and eliminate cancer cells using the body’s immune system. There are several immuno-oncology treatments available, including Immune cell therapy (CAR-T), monoclonal antibodies (mABs) and checkpoint inhibitors, cytokines and cancer vaccines.

MCE Small Molecule Immuno-Oncology Compound Library offers 783 bioactive tumor immunology compounds that target some important checkpoints such as PD1/PD-L1, CXCR, Sting, IDO, TLR, etc. This library is a useful tool for Immuno-oncology research.

Gastric Cancer (GC) is one of the most common malignant tumors in the world, ranking fourth in mortality rate globally. Because the early symptoms of stomach neoplasm are usually not obvious, are diagnosed with gastric cancer at terminal stage, and the relative survival rate within 5 years is very low. With the further understanding of the molecular characteristics of stomach neoplasm, many therapeutic targets for gastric cancer have been identified, and molecular targeted therapies such as CTLA-4, HER2 and immune checkpoint inhibitors have made rapid progress. Although survival rates for patients with gastric neoplasm have improved over the past few decades, the prognosis is still worrying. Therefore, there is an urgent need for new drugs to treat gastric cancer.

MCE designs a unique collection of 1,122 small molecules with definite or potential anti-gastric cancer activity, which is an important tool for studying the pathological mechanism of stomach neoplasm and developing drugs for stomach neoplasm.

The anti-cancer drug library meticulously collects all drugs approved by FDA and other major national drug regulatory authorities for cancer treatment. These drugs cover a variety of cancer types, including but not limited to lung cancer, breast cancer, colorectal cancer, leukemia, and other common cancers. The library includes a wide range of drugs, from classic chemotherapeutic agents to cutting-edge targeted therapies and immunotherapies. It contains various types of drug compounds with different mechanisms of action. There are cytotoxic drugs that directly kill cancer cells, as well as drugs that work by modulating the tumor microenvironment, inhibiting tumor angiogenesis, and activating the immune system. This diversity provides researchers with a broad range of perspectives and options for intervention strategies.

This library can be used for basic research on cancer treatment, exploring new targets and new mechanisms of drug action; Conducting drug reuse research to look for potential therapeutic effects of existing drugs on other cancer types or diseases; Or conducting research into combination drugs to optimize cancer treatment.

MCE has collected 271 small-molecule compounds with cancer indications, which are good tools for drug repurposing.

Dopamine receptor (DAR), widely distributed in the brain, plays a key role in regulating motor function, motivation, driving force and cognition. The role of DA is mediated by D1-type (D1, D5) and D2-type receptors (D2S, D2L, D3, D4), which are distributed in presynaptic, postsynaptic and extrasynaptic, projection neurons and interneurons. Each receptor has a different function. D1 and D5 receptors couple with G stimulation sites and activate Adenylyl cyclase. The activation of Adenylyl cyclase leads to the production of the second messenger cAMP, which leads to the production of protein kinase A (PKA), which leads to further transcription in the nucleus. D2 to D4 receptors are coupled to G inhibitory sites to inhibit adenylyl cyclase and activate potassium Ion channel. These receptors utilize phosphorylation cascades or direct membrane interactions to affect the functions of voltage-gated and neurotransmitter-gated channels, cytoplasmic enzymes, and transcription factors. Dopamine receptor plays an important role in daily life.

MCE designs a unique collection of 267 small molecules related to dopamine receptor. It is a good tool for screening drugs from nervous system disease.