The Structure-Function Linkage Database (SFLD) is a hierarchical classification of enzymes that relates specific sequence-structure features to specific chemical capabilities.
As of April 2019, the database is in static format, and is not being updated. Regular SFLD users may notice significant changes to the database, as interactive features are no longer available. However, the superfamily hierarchy may be browsed, and archived alignments, sequence similarity networks, and reaction similarity networks are available for download. Though SFLD sequence sets, alignments, and networks are not being updated, they may still provide a useful starting point for exploration and hypothesis generation.