This family contains the bacterial formate hydrogenlyase maturation protein HycH, which is approximately 140 residues long. This may be required for the conversion of a precursor form of the large subunit of hydrogenlyase 3 into a mature form [1].

1: Mutational analysis of the operon (hyc) determining hydrogenase 3 formation in Escherichia coli. Sauter M, Bohm R, Bock A; Mol Microbiol 1992;6:1523-1532. PMID:1625581