. "The reaction requires nickel to be bound to the precursor of the large subunit of hydrogenase 3." . "The endopeptidase uses the metal in the large subunit of [NiFe]-hydrogenases as a recognition motif." . "Belongs to peptidase family A31." . . . "HycI peptidase" . "This enzyme specifically removes a 32-amino acid peptide from the C-terminus of the precursor of the large subunit of E.coli hydrogenase 3 by cleavage at the C-terminal side of Arg(537)." .