Endopeptidases that belong to the bidirectional NAD-linked hydrogenase group. This group of endopeptidases are highly specific carboxyl-terminal protease (HoxW protease) which releases a 24-amino-acid peptide from HoxH prior to progression of subunit assembly. These bidirectional hydrogenases are heteropentamers encoded by the hox (hydrogen oxidation) genes, in which complex HoxEFU shows the diaphorase activity, and HoxYH constitutes the NiFe-hydrogenase.
Comment:based on sequence similarity to HybD structure, 1CFZ_A
Comment:Replacement of the homologous metal binding residues in HycI (hydrogenase 3 processing endopeptidase) by site-directed mutagenesis suggest a role in catalysis.