Copper is a Cofactor of the Formylglycine-Generating Enzyme.

Formylglycine-generating enzyme (FGE) is an O2 -utilizing oxidase that converts specific cysteine residues of client proteins to formylglycine. We show that CuI is an integral cofactor of this enzyme and binds with high affinity (KD =of 10-17  m) to a pair of active-site cysteines. These findings establish FGE as a novel type of copper enzyme.