The KEGG (Kyoto Encyclopedia of Genes and Genomes) resource is a comprehensive bioinformatics tool designed to integrate genomic, chemical, and network information to understand the functional meanings and utilities of cells or organisms from their genome data. Developed by the Kanehisa Laboratory at Kyoto University, KEGG consists of three main databases: the gene universe (GENES, SSDB, KO), the chemical universe (COMPOUND, GLYCAN, REACTION), and the protein network (PATHWAY). These databases represent building blocks and interaction networks responsible for various cellular processes. The gene universe captures ortholog/paralog relations and gene products, the chemical universe includes metabolic and biochemical compounds, and the protein network represents molecular interactions. KEGG also offers XML representations for automated analysis, an API for programmatic access, and new components like the KO database for ortholog grouping and the GLYCAN database for carbohydrate structures. The resource is widely used for analyzing molecular biological data and predicting higher-level cellular processes and organism behavior.The KEGG (Kyoto Encyclopedia of Genes and Genomes) resource is a comprehensive bioinformatics tool designed to integrate genomic, chemical, and network information to understand the functional meanings and utilities of cells or organisms from their genome data. Developed by the Kanehisa Laboratory at Kyoto University, KEGG consists of three main databases: the gene universe (GENES, SSDB, KO), the chemical universe (COMPOUND, GLYCAN, REACTION), and the protein network (PATHWAY). These databases represent building blocks and interaction networks responsible for various cellular processes. The gene universe captures ortholog/paralog relations and gene products, the chemical universe includes metabolic and biochemical compounds, and the protein network represents molecular interactions. KEGG also offers XML representations for automated analysis, an API for programmatic access, and new components like the KO database for ortholog grouping and the GLYCAN database for carbohydrate structures. The resource is widely used for analyzing molecular biological data and predicting higher-level cellular processes and organism behavior.