Enzyme Targets

Protein ubiquitination is an enzymatic post-translational modification in which an ubiquitin protein is attached to a substrate protein. Ubiquitination involves three main steps: activation, conjugation, and ligation, performed by ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s), respectively. Ubiquitination affects cellular processes such as apoptosis, cell cycle, DNA damage repair, and membrane transportation, etc. by regulating the degradation of proteins (via the proteasome and lysosome), altering the cellular localization of proteins, affecting proteins activity, and promoting or preventing protein-protein interactions. Deregulation of ubiquitin pathway leads to many diseases such as neurodegeneration, cancer, infection and immunity, etc.

MCE offers a unique collection of 257 small molecule modulators with biological activity used for ubiquitination research. Compounds in this library target the key enzymes in ubiquitin pathway. MCE Ubiquitination Compound Library is a useful tool for the research of ubiquitination regulation and the corresponding diseases.

Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels which include coronary heart disease, cerebrovascular disease, peripheral arterial disease, rheumatic heart disease, etc. CVDs are the number 1 cause of death globally. Smoking, unhealthy nutrition, aging population, lack of physical activity, arterial hypertension, or diabetes can promote cardiovascular disease like myocardial infarction or stroke. It is multifactorial and encompasses a multitude of mechanisms, such as eNOS uncoupling, reactive oxygen species formation, chronic inflammatory disorders and abnormal calcium homeostasis. Antioxidant, anti-inflammatory and anti-diabetes agents may reduce the cardiovascular disease risk.

MCE supplies a unique collection of 1,400 compounds with confirmed anti-cardiovascular activity. These compounds mainly target metabolic enzyme, membrane transporter, ion channel, inflammation related signaling pathways. MCE Anti-Cardiovascular Disease Compound Library can be used for cardiovascular diseases related research and high throughput and high content screening for new drugs.

Kinase is an enzyme that adds phosphate groups to other molecules. This process is known as phosphorylation. Protein phosphorylation is a key aspect in the regulation of a large number of cellular processes including cellular division, metabolism, signal transduction, and so on. There are over 500 kinases encoded by the human genome and it has been estimated that kinases regulate approximately 50% of cellular functions. Kinases are a large group of drug targets in drug discovery. Kinase inhibitors are an important class of drugs that block certain enzymes involved in diseases such as cancer and inflammatory disorders.

Kinase inhibitor library designed by MCE contains 2,673 kinase inhibitors and regulators mainly targeting protein kinases (VEGFR, EGFR, BTK, CDK, Akt, etc.), lipid kinases (PI3K, PI4K, SK, etc.) and carbohydrate kinases (Hexokinase), and is a useful tool for kinase drug discovery and related research.

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 605 protease inhibitors. MCE Protease Inhibitor Library is critical for drug discovery and development.

Protein serine/threonine kinases (PSKs) are protein kinases that use ATP as a high-energy donor molecule to transfer phosphate groups to serine/threonine residues of target protein. As an important signal transduction regulator, serine/threonine kinases can affect the function of target proteins by disrupting enzyme activity or binding of target proteins to other proteins. Serine/threonine kinases are involved in the regulation of immune response, cell proliferation, differentiation, apoptosis and other physiological processes. Serine/threonine kinase inhibitors are an important class of compounds that have been widely studied in cancer, chronic inflammation, autoimmune diseases, aging and other diseases.

MCE designs a unique collection of 1,286 serine/threonine kinase inhibitors, mainly targeting the receptor PKA, Akt, PKC, MAPK/ERK, etc, which is an effective tool for development and research of anti-cancer, anti-chronic inflammatory diseases, anti-autoimmune diseases and anti-aging compounds.

Transcription is the essential first step in the conversion of the genetic information in the DNA into protein and the major point at which gene expression is controlled. Transcription of protein-coding genes is accomplished by the multi-subunit enzyme RNA polymerase II and an ensemble of ancillary proteins, called transcription factors (TFs). Transcription factors play an important role in the long-term regulation of cell growth, differentiation and responses to environmental cues. Deregulated transcription factors contribute to the pathogenesis of a plethora of human diseases, ranging from diabetes, inflammatory disorders and cardiovascular disease to many cancers, and thus these proteins hold great therapeutic potential.

MCE offers a unique collection of 1,305 compounds with validated transcription factor targets modulating properties. MCE transcription factor-targeted compound library is an effective tool for researching transcription factors as drug targets as well as modulation of TFs for different therapeutic applications.

Metabolism is the set of life-sustaining chemical reactions in organisms that maintain cell homeostasis. Metabolic pathways are enzyme-mediated biochemical reactions that lead to biosynthesis (anabolism) or breakdown (catabolism) of molecules including glucose metabolism, lipid metabolism and amino acid or protein metabolism within a cell or tissue. As catalysts, enzymes are crucial to metabolism as they allow a reaction to proceed more rapidly and tregulate the rate of a metabolic reaction. Due to the importance of metabolic balance in the organism, the abnormal function of metabolic enzymes often leads to the occurrence of a variety of metabolic diseases, such as diabetes, obesity, cardiovascular disease, etc.

MCE designs a unique collection of 2,861 metabolic enzymes related small molecules, which is an important tool for studying the metabolic activities of organisms and developing drugs for metabolic diseases.

Membrane receptors, also known cell surface receptors or transmembrane receptors, are transmembrane proteins embedded into the plasma membrane which play an essential role in maintaining communication between the internal processes within the cell and various types of extracellular signals. They act in cell signaling by receiving (binding to) extracellular molecules, which are also called ligands. These extracellular molecules include hormones, cytokines, growth factors, neurotransmitters, lipophilic signaling molecules such as prostaglandins, and cell recognition molecules.

There are three kinds of membrane receptors: ion channel-linked receptors, enzyme-linked receptors and G-protein-linked receptors. They play important roles in keeping human normal physiologic processes. GPCRs and ion channels are important drug targets in drug discovery.

MCE provides a unique collection of 4,674 compounds targeting a variety of membrane receptors. MCE Membrane reeptor-targeted Compound Library can be used for membrane receptor-focused screening and drug discovery.

Protein protein interactions (PPI) have pivotal roles in life processes. The studies showed that aberrant PPI are associated with various diseases, including cancer, infectious diseases, and neurodegenerative diseases. The classic drug targets are usually enzymes, ion channels, or receptors, the PPI indicate new potential therapeutic targets. Therefore, targeting PPI is a new direction in treating diseases and an essential strategy for the development of new drugs.

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.

With the development of high-throughput technology, high-throughput screening is also gradually used for the identification of PPI inhibitors, but the compound library used for conventional target screening is not very effective in screening PPI inhibitors. To improve screening efficiency, MCE carefully selected 583 PPI inhibitors and mainly targeting MDM2-p53, Keap1-Nrf2, PD-1/PD-L1, Myc-Max, etc. MCE Protein-protein Interaction Inhibitor Library is a useful tool for PPI drug discovery and related research.

Antibiotics are types of antimicrobial products used for the treatment and prevention of bacterial infections. Antibiotics can kill or inhibit bacterial growth. Although the target of an antibiotic is bacteria, some antibiotics also attack fungi and protozoans. However, antibiotics rarely have an effect on viruses. The major mechanism underlying antibiotics is the inhibition or regulation of enzymes involved in cell wall biosynthesis, nucleic acid metabolism and repair, protein synthesis, or disruption of membrane structure. Many of these cellular functions targeted by antibiotics are most active in multiplying cells. Since there is often overlap in these functions between prokaryotic bacterial cells and eukaryotic mammalian cells, it is not surprising that some antibiotics have also been found to be useful as anticancer agents.

MCE supplies a unique collection of 638 antibiotics, including penicillins, cephalosporins, tetracyclines, macrolides, etc. MCE Antibiotics Library is a useful tool for anti-bacterial or anti-cancer drugs discovery.

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 134 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.

Hepatitis C virus (HCV) is a hepatotropic enveloped positive- strand RNA virus (family Flaviviridae) that infects the parenchymal cells of the liver. HCV infection is a significant public health burden. Globally, an estimated 71 million people have chronic hepatitis C virus infection. A significant number of those who are chronically infected will develop cirrhosis or liver cancer. To date, there is no vaccine against HCV, and combination pegylated alpha interferon (pIFN-) and ribavirin, the main standard-of-care treatment for HCV, is effective in only a subset of patients and is associated with a wide spectrum of toxic side effects and complications. More recently, new therapeutic approaches that target essential components of the HCV life cycle have been developed, including direct-acting antiviral (DAA) that specifically block a viral enzyme or functional protein and host-targeted agents (HTA) that block interactions between host proteins and viral components that are essential to the viral life cycle. However, the genetic diversity of HCV viruses and the stage of liver disease (i.e., cirrhosis) are revealing themselves as obstacles for effective, pan-genotypic treatments. There still exists a need for the discovery and development of new HCV inhibitors. In particular, since the future of HCV therapy will likely consist of a cocktail approach using multiple inhibitors that target different steps of infection, new antivirals targeting all steps of the viral infection cycle.

MCE offers a unique collection of 283 compounds with identified and potential anti-HCV activity. MCE Anti- Hepatitis C Virus Compound Library is a useful tool for discovery new anti-HCV drugs and other anti-infection research.

Copper is an important co-factor of all biological enzymes, but if the concentration exceeds the threshold of maintaining the homeostasis mechanism, copper will lead to cytotoxicity. This death mechanism has been named "Cuproptosis".

The mechanism of cuproptosis distinct from all other known mechanisms of regulated cell death, including apoptosis, pyroptosis, necroptosis, and ferroptosis.

Copper combine with the lipoylated components of the tricarboxylic acid cycle (TCA), leading to lipoylated protein aggregation and subsequent loss of iron-sulfur cluster proteins, ultimately resulting in protein toxicity stress and cell death. Studies have shown that the necessary factors for cuproptosis include the presence of glutathione, mitochondrial metabolism of galactose and pyruvate, and glutamine metabolism.

Targeted regulation of cuproptosis is a potential choice to treat cancer, rheumatoid arthritis, and other diseases. For example, up-regulation of LIPT1 may inhibit the occurrence and development of tumors by destroying TCA in mitochondria and then inducing cuproptosis.

MCE supplies a unique collection of 188 cuproptosis-related compounds, all of which act on the targets or signaling pathways related to cuproptosis and may have in inhibitory or activated effect on cuproptosis. MCE Cuproptosis Library is a useful tool for drug research related to cancer, rheumatoid arthritis, and other diseases.

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 6,016 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.

A histone modification, a covalent post-translational modification (PTM) to histone proteins, includes methylation, phosphorylation, acetylation, ubiquitylation, and sumoylation, etc. In general, histone modifications are catalyzed by specific enzymes that act predominantly at the histone N-terminal tails involving amino acids such as lysine or arginine, as well as serine, threonine, tyrosine, etc. The PTMs made to histones can impact gene expression by altering chromatin structure or recruiting histone modifiers. Histone modifications act in diverse biological processes such as transcriptional activation/inactivation, chromosome packaging, and DNA damage/repair. Deregulation of histone modification contributes to many diseases, including cancer and autoimmune diseases.

MCE owns a unique collection of 629 bioactive compounds targeting Epigenetic Reader Domain, HDAC, Histone Acetyltransferase, Histone Demethylase, Histone Methyltransferase, Sirtuin, etc. Histone Modification Research Compound Library is a useful tool for histone modification research and drug screening.

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 2,545 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.

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 696 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.

The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue. Inflammation is also the body's attempt at self-protection to remove harmful stimuli and begin the healing process. It’s part of the body's immune response. The immune system recognizes damaged cells, irritants, and pathogens, and inflammation begins the healing process. Inflammatory abnormalities are a large group of disorders that underlie a vast variety of human diseases. The immune system is often involved with inflammatory disorders, demonstrated in both allergic reactions and some myopathies, with many immune system disorders resulting in abnormal inflammation.

MCE designs a unique collection of 5,054 compounds that are useful tool for Immunology/Inflammation research or autoimmune inflammatory diseases drug discovery.

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 973 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.

Ion channel is a membrane-binding enzyme whose catalytic site is an ion conduction pore, which is opened and closed in response to specific environmental stimuli (voltage, ligand concentration, membrane tension, temperature, etc.). Ion channel provide pores for the passive diffusion of ions on the biofilm. Due to their high selectivity for ion, ion channel are generally classified as sodium (Na⁺ ), potassium (K⁺ ), calcium (Ca²⁺ ), chloride (Cl^- ), and non-specific cation channel. Ion channel is an important contributor to cell signal transduction and homeostasis. In addition to electrical signal transduction, ion channel also have many functions: regulating vascular smooth muscle contraction, maintaining normal cell volume, regulating glandular secretion, protein kinase activation, etc. Therefore, dysfunction of ion channel can lead to many diseases, and its mechanism research is particularly important.

MCE designs a unique collection of 1,129 small molecules related to ion channel, mainly targeting Na⁺ channel, K⁺ channel, Ca²⁺ channel, GABA receptor, iGluR, etc. It is an essential tool for research of cardiovascular diseases, Nervous system diseases and other diseases.

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 917 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.