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The items are arranged on a white background.](https://www.sigmaaldrich.com/content/dam/cms-commons/sigmaaldrich/marketing/global/images/applications/chemistry-and-synthesis/compound-screening-library.jpg "Compound Screening Library") Once a target protein implicated in a disease has been identified and validated, compound screening is performed to determine how small molecules interact with that specific target protein, by either activating or inhibiting it, for lead identification in drug discovery. * * * ## Related Products Slide 1 of 3 [![DyNAbind® DNA-Encoded Fragment Library](https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/images/324/465/d5e5dc94-3f0a-49b5-ae89-e4612dba08b5/640/d5e5dc94-3f0a-49b5-ae89-e4612dba08b5.jpg) \ Sigma-Aldrich \ DYNA001 \ DyNAbind® DNA-Encoded Fragment Library](https://www.sigmaaldrich.com/US/en/product/sial/dyna001) Quick View [![LOPAC®1280 - Small Scale](https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/images/395/550/bd04cceb-e029-40f7-88c4-ed631c39ec90/640/bd04cceb-e029-40f7-88c4-ed631c39ec90.jpg) \ Sigma-Aldrich \ LO4100 \ LOPAC®1280 - Small Scale](https://www.sigmaaldrich.com/US/en/product/sigma/lo4100) Quick View [![LOPAC®1280](https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/images/391/687/d714311a-0569-4a8c-82d5-9b1cca7e33f9/640/d714311a-0569-4a8c-82d5-9b1cca7e33f9.jpg) \ Sigma-Aldrich \ LO1280 \ LOPAC®1280](https://www.sigmaaldrich.com/US/en/product/sigma/lo1280) Quick View * * * ## Featured Categories [![Three colored squares displaying chemical structures and names. The yellow square features the structure of Furan, the turquoise square shows Thiophene with the letter "S," and the purple square displays the structure of Purine. Each square has the corresponding name prominently displayed.](https://www.sigmaaldrich.com/content/dam/cms-commons/sigmaaldrich/marketing/global/images/categories/building-blocks/Organic-Building-Blocks.jpg "Heterocyclic Building Blocks")](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/heterocyclic-building-blocks) [Heterocyclic Building Blocks](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/heterocyclic-building-blocks) We’re proud to offer a comprehensive portfolio of heterocyclic building blocks, one of the largest and most diverse families of molecular fragments used in organic synthesis. [Shop Products](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/heterocyclic-building-blocks) [![Three colored squares displaying chemical structures and names. The yellow square features the structure of Furan, the turquoise square shows Thiophene with the letter "S," and the purple square displays the structure of Purine. Each square has the corresponding name prominently displayed.](https://www.sigmaaldrich.com/content/dam/cms-commons/sigmaaldrich/marketing/global/images/categories/building-blocks/Organic-Building-Blocks.jpg "Heterocyclic Building Blocks")](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/organic-building-blocks) [Organic Building Blocks](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/organic-building-blocks) Find the basic components needed to drive your research forward in our portfolio of organic building blocks. Alkenesm alkanes, alkynes, arenes, allenes & more! [Shop Products](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/organic-building-blocks) [![A 3D molecular structure illustration on a yellow background. The model shows a ring structure with gray spheres representing carbon atoms, connected by white bonds. Various colored spheres represent different atoms: a red sphere (possibly oxygen), a green sphere, and a blue sphere. 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On the left, a blue hexagon features “2-Bromo-4-fluoropyridine,” with its corresponding molecular structure showing a pyridine ring with bromine (Br) and fluorine (F) substituents. In the center, a yellow square displays “2,2-Difluoroethylamine,” alongside its molecular formula NH2CHF2. On the right, a purple pentagon presents “1,1,1-Trifluoro-3-methyl-2-butene-1-ol,” with its molecular structure illustrating multiple fluorine (F) atoms and an alcohol group (OH) attached to a branched carbon chain.](https://www.sigmaaldrich.com/content/dam/cms-commons/sigmaaldrich/marketing/global/images/categories/building-blocks/fluorinated-building-blocks.jpg "Fluorine element from the periodic table")](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/fluorinated-building-blocks) [Fluorinated Building Blocks](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/fluorinated-building-blocks) With a vast offering of fluorinated building blocks, such as trifluoromethyl, difluoromethyl, triflate, and pentafluorosulfanyl substituents for your toolkit, we make it even easier to discover your target compounds. [Shop Products](https://www.sigmaaldrich.com/US/en/products/chemistry-and-biochemicals/building-blocks/fluorinated-building-blocks) * * * Overview Related Articles & Protocols Support To accelerate lead discovery, and thereby the rate of drug discovery, rapid and efficient screening technologies are essential. High-throughput screening (HTS) leverages automation and robotics for the quick analysis of large chemical compound libraries to ultimately detect compounds most suitable to pursue as drug candidates. DNA-encoded library (DEL) screening allows for mass conjugation of small molecule chemical compounds to short DNA fragments, so that a greater number of molecules can be examined for the desired activity and function simultaneously. In structure-based drug design screening, 3D structures of compounds are predicted using *in silico* techniques where entire libraries are docked into binding sites and the steric and electrostatic affinity between the compounds and target protein are evaluated. The highest-ranked compounds then progress to biological testing. Hit-to-lead (H2L) research evaluates the pharmacodynamic, physiochemical, and pharmacokinetic properties of hits to identify lead compounds for lead optimization and further analysis as potential candidates for drug development. [![Document Search](https://www.sigmaaldrich.com/content/dam/cms-commons/sigmaaldrich/marketing/global/images/ecommerce/document-search.png "Document Search")](https://www.sigmaaldrich.com/documents-search) [Looking for More Specific Information?](https://www.sigmaaldrich.com/documents-search) Visit our document search for data sheets, certificates and technical documentation. [Find Documents](https://www.sigmaaldrich.com/documents-search) [Shop All Lead Discovery Products](https://www.sigmaaldrich.com/search/lead-discovery?focus=products&page=1&perpage=30&sort=relevance&term=lead%20discovery&type=product) ## Related Articles - [Fragment-Based DNA-Encoded Library](https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/chemistry-and-synthesis/lead-discovery/fragment-based-dna-encoded-library-for-drug-discovery) Unprecedented access to large library drug discovery, Dynamic Library technology offers more reliable results than classical DEL approaches, library members selected for MedChem relevance, high chemical diversity, suitable for a number of targets - [Isotopically Labeled Steroid Standards](https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/analytical-chemistry/calibration-qualification-and-validation/labeled-steroids) We offer a wide variety of labeled bioactive compounds including steroids, vitamins, and their metabolites. - [Future of Drug Discovery with DNA Encoded Libraries](https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/chemistry-and-synthesis/lead-discovery/future-of-drug-discovery-with-dna-encoded-libraries) DNA encoded libraries (DELs) offer a paradigm shift in drug discovery by leveraging molecular biology and high-throughput screening. DELs offer a full high-throughput screening library in one vial. Along with our DEL data package, machine learning and AI can be utilized to determine even more information on targets. - [See All (4)](https://www.sigmaaldrich.com/US/en/search/facet-search?focus=sitecontent&term=facet-search) ### Find More Articles and Protocols Enter Keywords Search ## How Can We Help In case of any questions, please submit a [customer support request](https://www.sigmaaldrich.com/US/en/support/customer-support) or talk to our customer service team: Email [custserv@sial.com](mailto:custserv@sial.com) or call +1 (800) 244-1173 ## Additional Support - [Chromatogram Search](https://www.sigmaaldrich.com/chromatogram-search) Use the Chromatogram Search to identify unknown compounds in your sample. - [Calculators & Apps](https://www.sigmaaldrich.com/US/en/support/calculators-and-apps) Web Toolbox - science research tools and resources for analytical chemistry, life science, chemical synthesis and materials science. - [Customer Support Request](https://www.sigmaaldrich.com/US/en/support/customer-support) Customer support including help with orders, products, accounts, and website technical issues. - [FAQ](https://maestro.my.site.com/knowledgeportal/s/) Explore our Frequently Asked Questions for answers to commonly asked questions about our products and services. * * * __Featured Articles__ [Fragment-Based DNA-Encoded Library](https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/chemistry-and-synthesis/lead-discovery/fragment-based-dna-encoded-library-for-drug-discovery) Unprecedented access to large library drug discovery, Dynamic Library technology offers more reliable results than classical DEL approaches, library members selected for MedChem relevance, high chemical diversity, suitable for a number of targets [Isotopically Labeled Steroid Standards](https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/analytical-chemistry/calibration-qualification-and-validation/labeled-steroids) We offer a wide variety of labeled bioactive compounds including steroids, vitamins, and their metabolites. 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