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Normal mitochondrial function is critical for maintaining cellular homeostasis because mitochondria produce ATP and are the major intracellular source of free radicals. Cellular dysfunctions induced by intracellular or extracellular insults converge on mitochondria and induce a sudden increase in permeability on the inner mitochondrial membrane, the so-called mitochondrial membrane permeability transition (MMPT). MMPT is caused by the opening of pores in the inner mitochondrial membrane, matrix swelling, and outer membrane rupture. The MMPT is an endpoint to initiate cell death because the pore opening together with the release of mitochondrial cytochrome c activates the apoptotic pathway of caspases.

The normal operation of mitochondrial function is important for maintaining normal cell death and treatment of mitochondrial diseases. MCE offers a unique collection of 1,014 compounds with identified and potential mitochondrial protective activity. MCE Mitochondrial Protection Compound Library is critical for drug discovery and development.

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.

Cysteine proteases (CPs), a key enzyme family regulating physiological metabolism and mediating pathological processes (such as abnormal bone resorption, tumour invasion, and pathogen infection), represent a core therapeutic target for developing specific inhibitors in disease intervention. Currently reported CP inhibitors primarily achieve their inhibitory function by precisely binding to CP active pockets (e.g., S1-S4 non-primed regions or S1'-S2' primed regions) and forming covalent/non-covalent interactions with the active site cysteine residues, providing clear structural references for the development of novel inhibitors.

This compound library, designed based on the core strategy of "similarity-based known active structures", contains over 200 cysteine protease inhibitors. Leveraging AI-driven molecular screening technology, it retains the critical pharmacological and shape features of reported CP inhibitors, serving as a specialized tool for efficiently discovering novel cysteine protease inhibitors.

The majority of hypertensive patients have primary (or essential) hypertension, that is, hypertension in which secondary causes are not present. Management aims to control arterial pressure, prevent end-organ damage (cerebrovascular, cardiovascular, and renal), and reduce the risk of premature death.

Antihypertensive drugs may be divided into two broad groups, the first group being those which directly or indirectly block the renin–angiotensin system (RAS), for example, ACEIs, angiotensin receptor antagonists (ARAs), direct renin inhibitors (DRIs), and to a lesser extent β-blockers. The second group of drugs works by increasing water and sodium excretion, thereby reducing intravascular volume, or by causing vasodilatation through non-RAS pathways, for example, diuretics and calcium channel blockers (CCBs).

MCE offers a unique collection of 893 compounds with identified and potential antihypertensive activity. MCE Antihypertensive Compound Library is critical for antihypertensive drug discovery and development.

Heterocyclic compounds are cyclic organic compounds which contain at least one hetero atom, the most common heteroatoms are nitrogen, oxygen ,and sulfur. Heterocycles are common in biology, featuring a wide range of structures from enzyme co-factors to amino acids and proteins. On the one hand, heterocycles are common structural units in approved drugs and in medicinal chemistry targets in the drug discovery process. In addition, heterocycles have been found as a key structure in medical chemistry and also they are frequently found in large percent of biomolecules such as vitamins, natural products ,and biologically active compounds including antifungal, anti-inflammatory, antibacterial, antioxidant, antiallergic, anti-HIV, antidiabetic, anticancer activity.

MCE offers a unique collection of 6,484 heterocyclic compounds which can be used for drug discovery for high throughput screening (HTS) and high content screening (HCS). MCE heterocyclic compound library is critical for drug discovery and development.

DNA is prone to numerous forms of damage that can injure cells and impair fitness. Cells have developed an array of mechanisms to repair these injuries. Proliferating cells are especially vulnerable to DNA damage due to the added demands of cellular growth and division. Cell cycle checkpoints represent integral components of DNA repair that coordinate cooperation between the machinery of the cell cycle and several biochemical pathways that respond to damage and restore DNA structure. By delaying progression through the cell cycle, checkpoints provide more time for repair before the critical phases of DNA replication, when the genome is replicated, and of mitosis, when the genome is segregated. Loss or attenuation of checkpoint function may increase spontaneous and induced gene mutations and chromosomal aberrations by reducing the efficiency of DNA repair.

MCE owns a unique collection of 3,313 cell cycle/DNA damage-related compounds which can be used in the research of the same.

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.

Epigenetics involves heritable phenotypic changes that occur without alterations to the underlying DNA sequence. Key mechanisms include DNA methylation, histone modifications, and regulation by small non-coding RNAs such as microRNAs. By modifying DNA, histones, or RNA—while leaving their primary sequences intact—these processes influence molecular function and regulation, thereby playing critical roles in cellular differentiation, embryonic development, gene expression control, aging, and diseases such as cancer.

MCE provide a unique collection of 297 epigenetics-related compounds. For each regulatory target and its subtype, 3 to 5 highly specific representative compounds have been retained, which can be used in epigenetic and related disease research.

Kinases are enzymes that catalyze the addition of phosphate groups to substrate molecules, a process known as phosphorylation. Protein phosphorylation serves as a critical regulatory mechanism for numerous cellular processes, including cell division, metabolism, and signal transduction. The human genome encodes over 500 kinases, which collectively regulate approximately 50% of cellular functions. Due to their pivotal roles, kinases represent one of the most important target classes in drug development.

Kinase inhibitors can selectively block the activity of disease-associated kinases, making them valuable therapeutics for conditions such as cancer and inflammatory diseases. FDA-approved kinase inhibitors have undergone extensive preclinical and clinical studies, demonstrating high bioactivity, favorable safety profiles, and good bioavailability, rendering them suitable for investigating new therapeutic indications.

Fragment-based drug discovery (FBDD) offers a strategic advantage by categorizing fragment hits according to their functional groups. This approach facilitates both the further optimization of these hits and the rational design of larger compounds through fragment combination. The amine functional group plays a vital role in drug development, as evidenced by its presence in many marketed drugs like Galantamine, Tacrine, and Rivastigmine. It is instrumental in enhancing solubility, improving bioavailability, and ensuring shelf-life stability—all critical factors for drug efficacy.

MCE offers a collection of 19,532 amine fragments for drug discovery. All of these compounds adhere to the Rule of Three (RO3) criteria for drug-likeness, which MCE offers a collection of 19,532 amine fragments for drug discovery, all of which stipulates a molecular weight ≤ 300 Da, ≤ 3 hydrogen bond donors, ≤ 3 hydrogen bond acceptors, and a cLogP ≤ 3.

Cell death is a core biological process that maintains homeostasis in multicellular organisms, playing a dual role in life activities. On one hand, cell death participates in physiological processes such as cell renewal and damage repair through precise regulation; on the other hand, it actively eliminates damaged, infected, or cancerous cells, thereby blocking pathological progression and preserving organism health. Cell death not only ensures the normal development and growth regulation of organisms but is also closely associated with the occurrence and development of various diseases. Numerous studies have shown that specific types of programmed cell death play critical roles in disease progression, providing an important theoretical basis for developing novel therapeutic strategies by regulating cell death pathways.

MCE offers 22 types of commonly used cell death inhibitors, such as apoptosis, ferroptosis, pyroptosis, and cuproptosis, suitable for use as positive controls in the study of novel cell death mechanisms.

Oxygen homeostasis regulation is the most fundamental cellular process for adjusting physiological oxygen variations, and its irregularity leads to various human diseases, including cancer. Hypoxia is closely associated with cancer development, and hypoxia/oxygen-sensing signaling plays critical roles in the modulation of cancer progression.

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that functions as a master regulator of oxygen homeostasis. A variety of HF-1 target genes have been identified thus far which encode proteins that play key roles in critical developmental and physiological processes including angiogenesis/vascular remodeling, erythropoiesis, glucose transport, glycolysis, iron transport, and cell proliferation/survival.

HIF-1 is a heterodimeric transcription factor consisting of a constitutively expressed β-subunit and an oxygen-regulated α-subunit. The unique feature of HIF-1 is the regulation of HIF-1α expression and activity based upon the cellular O₂ concentration. Under normoxic conditions, hydroxylation of HIF-1α on these different proline residues is essential for HIF proteolytic degradation by promoting interaction with the von Hippel-Lindau tumor-suppressor protein (pVHL) through hydrogen bonding to the hydroxyproline-binding pocket in the pVHL β-domain. As oxygen levels decrease, hydroxylation of HIF decreases; HIF-1α then no longer binds pVHL, and becomes stabilized, allowing more of the protein to translocate to the cell’s nucleus, where it acts as a transcription factor, upregulating (often within minutes) the production of proteins that stimulate blood perfusion in tissues and thus tissue oxygenation.

MCE offers a unique collection of 4,029 oxygen sensing related compounds targeting HIF/HIF Prolyl-Hydroxylase, MAPK/ERK, PI3K/AKT signaling pathways, etc. MCE Oxygen Sensing Compound Library is a useful tool to study hypoxia, oxidative stress and discover new anti-cancer drugs.

Oceans cover more than 70% of the Earth’s surface and host a huge species diversity. Marine organisms are considered the most recent source of bioactive natural products after terrestrial plants and nonmarine microorganisms. Marine biological sources are taxonomically diverse and include sponges, tunicates, corals, mollusks, fungi, and sediment-derived bacteria.

Marine organisms can produce a plethora of small molecules with novel chemical structures and potent biological properties, being a rich source for the discovery of pharmacologically active compounds, already with several marine-derived agents approved as drugs. Ziconotide, a peptide originally discovered in a tropical cone snail, was the first marine-derived compound to be approved in the United States in December 2004 for the treatment of pain. Then, in October 2007, Trabectedin became the first marine anticancer drug to be approved in the European Union.

MCE offers a unique collection of 63 marine-sourced natural products which can be used for drug discovery for high throughput screening (HTS) and high content screening (HCS). MCE marine-sourced natural product library is an important source for drug discovery and development.

Metabolomics, positioned as the systemic characterization of small-molecule metabolites within biological systems, has emerged as an indispensable analytical platform in both fundamental research and translational applications across plant sciences, microbial biotechnology, and biomedical investigations. Functioning as a critical component in multi-omics integration, this discipline deciphers the intricate molecular networks operating downstream of genomic, transcriptomic, and proteomic regulation, thereby capturing the dynamic biochemical phenotype closest to organismal functionality. The metabolome, comprising endogenous compounds with molecular weights typically below 1500 Da, serves as the functional readout of cellular processes and environmental interactions, where perturbations in metabolic networks are frequently implicated in disease pathogenesis. Such unique attributes have propelled metabolomics into a pivotal role in pharmacological research, particularly in target deconvolution, pharmacodynamic assessment, and mechanistic elucidation of pathological processes.

MCE can provide 5,923 mass spectrometry human metabolites that can be used for metabolite identification and quantification, functional cell detection and phenotypic screening of mass spectrometry.

A diverse compound library with favorable ADMET properties (Absorption, Distribution, Metabolism, Excretion, and Toxicity) is crucial in drug discovery. Early evaluation of ADMET properties allows for the exclusion of molecules with unfavorable profiles at the initial stages, thereby reducing the risk of late-stage development failures, lowering R&D costs, and accelerating optimization of lead compounds. Based on predictions from ADMET-related AI algorithms, the compounds in this library are predicted to exhibit favorable oral bioavailability (F > 30%), reasonable plasma protein binding (PPB < 98%), minimized CYP3A4 inhibition potential (inhibition probability < 50%, CYP3A4 is the most critical drug-metabolizing enzyme in the cytochrome P450 family) , low toxicity profiles, with 140 potentially toxic substructures pre-identified and excluded via substructure searching to eliminate compounds containing hazardous fragments. The diversity library enables broad applicability in high-throughput screening (HTS) and high-content screening (HCS).

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is central to signaling by cytokine receptors, a superfamily of more than 30 transmembrane proteins that recognize specific cytokines, and is critical in blood formation and immune response. Canonical JAK/STAT signaling begins with the association of cytokines and their corresponding transmembrane receptors. Activated JAKs then phosphorylate latent STAT monomers, leading to dimerization, nuclear translocation, and DNA binding. In mammals, there are four JAKs (JAK1, JAK2, JAK3, TYK2) and seven STATs (STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, STAT6). Since the JAK/STAT pathway plays a major role in many fundamental processes, such as apoptosis and inflammation, dysfunctional proteins in the pathway may lead to a number of diseases. For example, alterations in JAK/STAT signalling can result in cancer and diseases affecting the immune system, such as severe combined immunodeficiency disorder (SCID).

MCE provides 704 compounds that can be used in the study of the JAK/STAT signaling pathway and related diseases.

Coagulation, also known as clotting, is the process in which blood changes from a liquid to a solid gel to form a blood clot. Thrombin, which is accurately and evenly generated in the injured part of blood vessels, is a key effector enzyme of the blood coagulation system and participates in many important biological processes, such as platelet activation, fibrinogen conversion to fibrin network, coagulation feedback amplification, etc. At the same time, to avoid the accidental formation of thrombus in the body, there is also an anticoagulant mechanism that inhibits blood coagulation.

Normal coagulation mechanism represents a balance between the pro-coagulant pathway in the injured site and anti-coagulant pathway beyond it. The blood coagulation system may be out of balance during the perioperative period or critical illness, which may lead to thrombosis or excessive bleeding. Therefore, the physiological study of coagulation balance is an important basis for clinical diagnosis and treatment of the abnormal coagulation process.

MCE supplies a unique collection of 1,437 compounds targeting key proteins in coagulation and anti-coagulation system. MCE Coagulation and Anti-coagulation Compound Library is a useful tool for study the mechanism of coagulation and anticoagulation.

Protein phosphorylation is a key post-translational modification underlying the regulation of many cellular processes. Phosphatases and kinases contribute to the regulation of protein phosphorylation homeostasis in the cell. This reversible regulation of protein phosphorylation is critical for the proper control of a wide range of cellular activities, including cell cycle, proliferation and differentiation, metabolism, cell-cell interactions, etc.

Protein phosphatases have evolved in separate families that are structurally and mechanistically distinct. Based on substrate specificity and functional diversity, protein phosphatases are classified into two superfamilies: Protein serine/threonine phosphatases and Protein tyrosine phosphatases. Ser/Thr phosphatases are metalloenzymes belonging to two major gene families termed PPP (phosphoprotein phosphatase) and PPM (metal-dependent protein phosphatases), whereas protein tyrosine phosphatases (PTPs) belong to distinct classes of enzymes that utilize a phospho-cysteine enzyme intermediate as a part of their catalytic action.

MCE supplies a unique collection of 175 phosphatase inhibitors that mainly targeting protein tyrosine phosphatases (PTPs) and serine/threonine-specific protein phosphatases. MCE Phosphatase Inhibitor Library is a useful tool for phosphatase drug discovery and related research.

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.

Lipids are important energy storage substances in the human body. They are involved in the regulation of cell structure and function, as well as signaling pathways and gene expression. Abnormal lipid levels in tissues or their dysregulation can lead to various diseases. These include obesity, type 2 diabetes, non-alcoholic fatty liver disease, neurodegenerative diseases, infections, and cancer. Therefore, maintaining normal levels of lipid metabolism is critical to overall health.

One of the key features of cancer is aberrant lipid metabolism. This includes alterations in lipid uptake, lipid desaturation, neolipogenesis, lipid droplets, and fatty acid oxidation in cancer cells. These changes all contribute to cellular survival in an ever-changing microenvironment. They do this by modulating feed-forward oncogenic signals and key oncogenic functions. Additionally, they affect oxidative stress, other types of stress, immune responses, and intercellular communication. Alterations in lipid metabolism have a strong impact on the properties of cancer stem cells. This includes aspects such as self-renewal, differentiation, invasion, metastasis, drug sensitivity, and resistance. Furthermore, these alterations also modulate T cell responses.

MCE can offer 145 metabolites of lipid metabolism pathways, which can be used for drug screening in cancer, immune-based diseases, metabolic diseases, and other diseases.

In drug discovery and development (R&D) area, target binding and druggability optimization are core processes. Among these attributes, high solubility is critical for a compound to achieve druggability, as it directly impacts the progress of drug R&D. Superior solubility ensures the rapid dissolution and uniform distribution of drug molecules in vivo, thereby enhancing bioavailability and effectively mitigating issues such as suboptimal efficacy, increased dosage requirements, or exacerbated toxic and side effects arising from insufficient solubility.

From the perspective of medicinal chemistry, high-solubility drug fragments serve as high-quality "molecular building blocks". Based on these fragments, lead compounds with potential druggability can be rapidly screened out, which significantly shortens the drug R&D cycle and reduces R&D costs. Meanwhile, the high-solubility drug fragment library can provide diverse options for drug development in different therapeutic areas, offer solutions for the solubility defects of existing clinical drugs, and facilitate the development of novel, highly effective targeted drugs with higher bioavailability and better safety profiles.

MCE has collected and compiled 2,527 experimentally validated small-molecule fragments with high solubility. These fragments can be directly used for drug molecular design, providing high-quality pre-validated solubility fragments that significantly improve the efficiency of lead compound screening and accelerate the progress of drug R&D.

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.

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.

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.

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.