Compound

POI (Protein of Interest) refers to the target protein, namely the disease-causing protein or key functional protein that undergoes degradation or functional modulation in molecular glue-mediated processes. The Molecular Glue POI Library consists of a series of fragments that can specifically bind to different types of POIs. As key components of molecular glues, these ligands form stable interactions with target proteins, laying the foundation for molecular glues to induce the interaction between POIs and E3 ubiquitin ligases. The covered POIs include various types such as cancer-associated GSPT1, androgen receptors, and abnormally aggregated proteins linked to neurodegenerative diseases.

This fragment library can be applied to the screening and optimization of targeted protein degraders. By screening ligands with high affinity and strong selectivity for specific POIs from the library, core structures can be identified to develop novel molecular glues. For instance, optimization of ligands targeting GSPT1 has yielded molecular glue degraders with enhanced degradation activity. Since many POIs are difficult to drug due to the lack of traditional small-molecule binding pockets, some ligands in the POI Ligand Library can modulate such POIs by inducing protein-protein interactions, thereby further expanding the scope of drug discovery for undruggable targets.

MCE has compiled a POI Fragment Library comprising thousands of POI fragments with molecular weights ranging from 150 to 400. This compound library can be widely applied in Molecular Glue research and development.

RNA is crucial for the regulation of numerous cellular processes and functions. With the in-depth study of disease mechanisms, processes such as RNA expression, splicing, translation, and stability regulation have become new targets for disease intervention. RNA has provided new therapeutic modalities for metabolic diseases, genetic disorders, and cancer patients, resulting in several innovative drugs.

MCE R&D team collected small molecules targeting RNA from the PDB, R-BIND, ROBIN, and internal database as the positive dataset, and non-targeting RNA small molecules from ROBIN as the negative dataset. Based on the GeminiMol pre-trained model, we encoded the molecules and calculated over 1700 molecular descriptors using Mordred as inputs for the model. Subsequently, we employed 13 deep learning models to learn from the data. All of which yielded good training results, with AUROCs greater than 0.75. Ultimately, we selected the Finetune model to screen HY-L901P, which exhibited the best classification performance, achieving an AUROC of 0.82 and a prediction accuracy of 0.76. We then applied filtering based on StaR rules (with at least two of the following properties: cLogP ≥ 1.5, Molar Refractivity ≥ 4, Relative Polar Surface Area ≤ 0.3) to obtain a library containing approximately 5,000 small molecule compounds targeting RNA. This library serves as a valuable tool for screening small molecules that interact with RNA.

MCE 18 stands for Medicinal Chemistry Evolution 2018. This metric was established based on structural data of 28,161 patented lead molecules, 1,370 marketed innovative drugs, and nearly 30,000 investigational candidates from preclinical to Phase III stages across 23 major global pharmaceutical companies from 1950 to 2018. After scaffold clustering analysis, a scoring model was constructed by integrating five three dimensional scaffold characteristics, including aromatic rings (AR), non aromatic heterocycles (NAR), chiral centers (CHIRAL), spirocycles (SPIRO), and the sp³ carbon ratio in cyclic and acyclic moieties, enabling quantitative assessment of molecular scaffold novelty and three dimensional complexity.

According to the score distribution of patented molecules, the top 25% of the original patent dataset was defined as the high novelty region. MCE 18 high scoring compounds selected based on this criterion can effectively avoid scaffold patent conflicts and intellectual property risks from the source. Molecules in this range typically feature a high sp³ carbon ratio, abundant chiral centers, spirocycles, and fused heterocycles with prominent three dimensional conformations. Their spatial properties allow precise matching to complex non traditional undruggable target pockets such as PPI interfaces and allosteric sites, making them ideal structural types for early stage screening of First in class drugs.

MCE‑18 Novelty Focused drug‑Like library strictly selects molecules from the aforementioned high scoring range, containing more than 10,000 premium drug like molecules with highly diverse scaffolds and rich 3D diversity. It can be used for high throughput screening of well established targets such as kinases, GPCRs, and proteases, and is especially suitable for hit identification in allosteric modulation, protein–protein interactions, and various undruggable orphan targets, fully supporting early stage drug discovery for cutting edge innovat

Built on druggable heterocyclic backbones with tunable electrophilic warheads (halogens, cyano groups), our electrophilic heterocyclic fragment library targets non-conserved cysteine/lysine residues and screens covalent ligands through an electrophile-first workflow. It generates high-quality dual-functional fragments for KRAS, BTK and other popular targets, supporting MS and DEL high-throughput screening to accelerate covalent drug lead discovery.

MCE Electrophilic Heterocyclic Fragment Library Built on druggable heterocyclic backbones with tunable electrophilic warheads (halogens, cyano groups), our electrophilic heterocyclic fragment library targets non-conserved cysteine/lysine residues and screens covalent ligands through an electrophile-first workflow. It generates high-quality dual-functional fragments for KRAS, BTK and other popular targets, supporting MS and DEL high-throughput screening to accelerate covalent drug lead discovery.

Accumulating evidence has revealed that intestinal microbiota play an important role in human health and disease, including cardiovascular diseases, inflammatory bowel disease, diabetes, obesity, cancer, and depression, etc. Changes in the composition of gut microbiota associated with disease, referred to as dysbiosis, have been linked to pathologies. Indeed, the gut microbiome functions like an endocrine organ, generating bioactive metabolites which play important roles in human metabolism, health, and disease. Gut microbiome has become a novel therapeutic target for many diseases. Analysis and identification of gut microbial metabolite will contribute to the development of therapeutic methods.

In order to meet the need of gut microbiome research, MCE carefully selected a unique collection of 475 gut microbial metabolites. MCE gut microbial metabolite library is a powerful tool for gut microbiome research and gut microbiome -related drug discovery.

Protein protein interactions (PPI) have pivotal roles in life processes. The studies showed that aberrant PPI are associated with various diseases. However, the design of modulators targeting PPI still faces tremendous challenges, such the difficult PPI interfaces for the drug design, lack of ligands reference, lack of guidance rules for the PPI modulators development and high-resolution PPI proteins structures.

The PPI Library comprises molecules of various sizes, frameworks, and shapes ranging from fragment-like entities to macrocyclic derivatives designed as secondary structure mimetics or as epitope mimetics. The designs cover β-turn / loop mimetics and α-helix mimetics. Since helices present at the interface in 62% of all protein-protein interactions. This library focused on designs including mimics with the substitution geometry of an a-helices, as well as designs that mimic the location of “hot-spot” side chains in helix-mediated PPIs.

Neuropeptides are small proteins produced and released by neurons through the regulation of secretory pathways, expressed in neurons and have transmitter or co-transmitter functions, and are used as nerve substrates. Neuropeptides are by far the largest and most diverse signaling molecules in the brain and have been implicated in the development of diseases and drugs. Neuropeptides are involved in inflammatory and immune diseases and have an impact on epithelial, vascular, and connective tissue cells proliferation and tissue repair. Studies have shown that neuropeptides are particularly important when the nervous system is challenged, such as stress, injury, or substance abuse. Substance P is a neuropeptide that acts as a neurotransmitter and neuromodulator in the central nervous system and is currently in clinical research and has been shown to be involved in inflammatory processes and pain.

MCE can provide 128 neuropeptides that can be used for scientific research.

19F-NMR has proved to be a detection mode in fragment-based drug discovery (FBDD) for studies of protein structure and interactions. 19F shows high sensitivity for NMR detection, and the exquisite sensitivity of 19F chemical shifts and linewidths to ligand binding all make it a valuable approach in FBDD.F (Fluorine) -Fragments can be used for 19F-NMR detection after binding to target proteins, and can be used as an effective 19F-NMR tool for FBDD.

MCE designs a unique collection of 5,077 F-fragments, all of which obey a heuristic rule called the “Rule of Three (RO3)”, in which molecular weight ≤300 Da, the number of hydrogen bond donors (H-donors) ≤3, the number of hydrogen bond acceptors (H-acceptors) is ≤3 and cLogP is ≤3. This F-fragments library is an important source of lead-like drugs.

PD-1/PD-L1 are key immune checkpoint targets that suppress T-cell-mediated anti-tumor immunity, representing a major focus in cancer immunotherapy. While antibody drugs dominate the clinic, they are limited by administration challenges and immune-related side effects. Small-molecule PD-1/PD-L1 inhibitors, with oral availability, good tissue penetration and low cost, have emerged as a promising next-generation strategy.

A PD-1/PD-L1 lead-like library was built via a five-step virtual screening process. After collecting 8,947 inhibitors from BindingDB and PubChem and filtering by activity and duplicates, AI similarity screening was performed using GeminiMol. Key pharmacophores were extracted from the PPI interface of co-crystal structures, and molecular was screened via a pharmacophore model, effectively enhancing target activity.

Containing 10,000 structurally diverse and drug-like molecules well-matched to the PD-L1 pocket, the library supports virtual docking, high-throughput screening and hit discovery, enabling efficient and rapid development of small-molecule immunotherapies.

Pattern Recognition Receptors (PRRs) are a crucial class of protein molecules expressed in cells of the innate immune system. The core function of Pattern Recognition Receptors is to recognize Pathogen-Associated Molecular Patterns (PAMPs) and Damage-Associated Molecular Patterns (DAMPs). Upon recognizing and binding to PAMPs or DAMPs, PRRs rapidly initiate intracellular signaling pathways (such as the NF-κB, IRF, and inflammasome pathways). This triggers the production of inflammatory factors, chemokines, and type I interferons, thereby initiating inflammatory responses to eliminate pathogens or repair damage. PRRs represent the body's first line of defense against infection, and the rapidity and broad specificity of their response are crucial for host survival. However, aberrant activation of PRR signaling is also a cause of many chronic inflammatory diseases, autoimmune disorders, and neurodegenerative diseases. Therefore, precisely regulating PRR activity has become a key therapeutic strategy for these conditions.

MCE has cataloged 338 inhibitors targeting key PRRs, such as NLRs, TLRs, C-type Lectin Receptors (CLRs), and cGAS, to support drug discovery efforts for chronic inflammatory diseases.

Fragment-based drug development (FBDD) is a strategy for drug discovery that can be applied both academically and commercially to enhance the identification of some non-drug targets. Fragment-based drug development has identified low molecular weight molecules (<300 Da) capable of binding to related macromolecules. These fragments can cover a wide chemical space and are easy to optimize later. Currently, several fragment-based drugs have entered clinical trials, of which two drugs, Vemurafenib and Venetoclax, have been approved for marketing.

Based on Tanimoto coefficient, MCE uses similarity algorithm to carefully select 2,196 high-structurally diverse 'RO3' compliant fragment molecules from large-scale fragment molecules, which can be applied to fragment based drug development.

“BioDesign” approach incorporates key structural features of known pharmacologically relevant natural products (e.g. alkaloids and other secondary metabolites) into synthetically feasible medicinal chemistry scaffolds. In order to identify the privileged pharmacophores, ring systems and linkers, we have carried out statistical analysis of structural features of natural products, marketed drugs, and drug candidates.

Saturated, fused ring, spiro, and bridged systems with a tendency towards multiple chiral centers are highly privileged among natural products and marketed drugs yet these structures are very poorly represented in commercial libraries. This library addressed this market need by incorporating these privileged elements into the design of novel synthetic molecules with high molecular framework diversity, multiple stereogenic centers (≥2), and degree of saturation (Fsp3 > 0.5).

Metabolomics is the large-scale study of cellular metabolic complement, with proven utility in both basic and applied studies of plants, microorganisms, and mammals. As an important tool for the study of complex biological systems, metabolomics monitors the complex molecular networks that exist in the natural flow of information from genes to mRNA and proteins to organisms. The metabolome is composed of biomolecules that most closely resemble the phenotype of an organism, and changes in its composition can easily lead to the production of diseases. Therefore, metabolomics has received much attention in drug target discovery, drug response and translational research of disease mechanisms. Mass spectrometry-based metabolomics methods can simultaneously detect and quantify thousands of metabolite signatures, thereby characterizing the pathophysiological mechanisms of various biomedical symptoms.

MCE can provide 661 mass spectrometry human endogenous metabolites that can be used for metabolite identification and quantification, functional cell detection and phenotypic screening of mass spectrometry.

Linkers play a necessary role in the physicochemical properties and biological activity of the bifunctional molecule. These linkers are not a simply connection of two functional modules together, but its design and nature directly affect the stability, activity, selectivity, pharmacokinetics, and ultimately the therapeutic efficacy of the entire molecule. The length of the linker determines the extent of interaction between the two ligands and thus the maximum activity of the PROTAC molecule.

MCE has collected 1,213 PROTAC Linkers can be used for the design and synthesis of bifunctional molecules.

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 23 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.

Targeted cancer therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecular targets that are involved in the growth, progression, and spread of cancer.

There are several different types of targeted therapy. The most common types are small-molecule drugs and monoclonal antibodies. Small-molecule drugs are small enough to enter cells easily, so they are used for targets that are inside cells, while monoclonal antibodies are usually used for targets that are located outside the cells. Because of high specificity, low side effect and potent anticancer activity, targeted therapy has become the mainstream of new anti-tumor drugs. Various targeted therapies have been approved by FDA and used in the treatment of diseases.

MCE carefully collects a unique of 106 targeted therapy drugs used in cancer treatment. MCE Targeted therapy drug library is a useful tool for the research of targeted therapy.

Biotoxins, also referred to as natural toxins, are chemical substances produced by plants, animals, or microorganisms that exert toxic effects on other living organisms. Due to unique biological activities, biotoxins have been widely applied in molecular biology, physiology, pharmacology, and the clinical diagnosis and treatment of various human diseases, becoming an important source of natural drug development. Biotoxins can specifically bind to and interfere with intracellular signaling molecules or receptors, thereby altering cellular signaling processes. Leveraging this characteristic, biotoxins can be used to study the regulatory mechanisms of cellular signaling pathways. For example, neurotoxins such as snake venom peptides can be used to investigate the functional regulation of neurotransmitter receptors and ion channels. Additionally, biotoxins have demonstrated significant potential in drug development across various fields, including neurological diseases, cardiovascular diseases, anticoagulation, and anti-cancer therapies. With advancements in high throughput screening, structural optimization, and antibody-toxin conjugation technologies, numerous biotoxins or their structural analogs have been successfully brought to market, such as Ziconotide, Captopril, Bivalirudin, and Eptifibatide.

MCE offers 91 types of biotoxins, including neurotoxins, cardiotoxins, mycotoxins, and more.

Antimicrobial Peptides (AMPs), also known as antimicrobial peptides or antibiotic peptides, are a class of polypeptides encoded by specific genes in various biological cells and induced by external stimuli. They exhibit broad-spectrum bioactivity against bacteria, fungi, viruses, protozoa, and even tumor cells. AMPs serve as crucial effector molecules in the host's innate immune system.Due to their wide antimicrobial spectrum, low toxicity to normal cells of higher animals, high safety profile, low tendency to induce resistance, and additional benefits such as immune enhancement and antioxidant effects, antimicrobial peptides hold significant promise in new drug development.

MCE offers 58 types of antimicrobial peptides, which can be applied in high-throughput screening for research in anti-infection therapies, immunotherapy, anticancer drug development, and agricultural disease control.

Macrocyclic scaffolds are increasingly valued in modern drug discovery for their exceptional activity against undruggable targets (proteases, kinases, PPIs). 2026 marks a key commercial breakthrough for oral macrocyclic peptides: enlicitide, the world’s first oral PCSK9 macrocyclic peptide, has received FDA approval. Macrocyclic candidates targeting KRAS and other classic undruggable targets have also entered clinical development, validating macrocyclization as an effective strategy to overcome druggability barriers.

Two core R&D directions lead current macrocyclic drug design: AI-driven de novo generation and structural optimization of small-molecule macrocycles, and macrocyclic peptides based on sequence design and conformational engineering. Macrocycle druggability hinges on embedded linkers, which determine cyclization efficiency, final conformation and drug-like properties. Bifunctional reaction orthogonality is the core linker selection criterion. Our linker library enables stepwise intramolecular cyclization with suppressed side reactions, accommodates varied ring sizes, and covers three key reaction systems: amide condensation, nucleophilic substitution and CuAAC click chemistry.

Built on classical macrocyclization systems, the library is processed through reaction classification, bifunctional orthogonality evaluation, novelty clustering and redundancy removal, with PROTAC long-chain and ADC cleavable linkers explicitly excluded. Featuring rigid, semi-rigid and flexible scaffolds, it is widely applicable to small-molecule macrocycle synthesis and linear peptide cyclization.

Plant hormones are natural signaling molecules synthesized by plants themselves, serving as crucial chemical messengers that exert physiological effects on plants at extremely low concentrations. They coordinate cellular growth, division, differentiation, and organ formation, helping plants adapt to environmental changes. Major categories include abscisic acid, auxins, gibberellins, cytokinins, ethylene, and brassinosteroids, among others.

MCE has included 44 plant hormones, which can be used for identification in plant metabolomics and related botanical research.