BRENDA is a comprehensive database of enzyme information. It contains enzyme function data from primary literature sources including enzyme name, organism, EC number, literature citations, two dimensional images, and links to other databases. It's free, but users must register.
An enzyme nomenclature database based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB); it describes each type of characterized enzyme for which an EC (Enzyme Commission) number has been provided .
The Ligand Chemical Database for Enzyme Reactions (LIGAND) is designed to provide the linkage between chemical & biological aspects of life in light of enzymatic reactions.
A collection of information about restriction enzymes, methylases, the microorganisms from which they have been isolated, recognition sequences, cleavage sites, methylation specificity, the commercial availability of the enzymes, & references.