The Metal MACiE database has the purpose of annotating both properties and functions of the metal ions involved in the catalytic reactions of enzymes. The database is an extension of the MACiE databaseand is the result of a collaborative project among three institutes: the Magnetic Resonance Center (University of Florence),
the European Bioinformatics Institute and the Unilever Center (University of Cambridge)

The Metal MACiE database currently covers 75% of the metal-dependent EC sub-sub classes.