3.4.23.51 precursor of the large subunit of hydrogenase 3 + H2O - 3.4.23.51 precursor of the large subunit of hydrogenase 3 + H2O i.e. HycE 3.4.23.51 precursor of the large subunit of hydrogenase 3 + H2O HycI involved in the C-terminal processing of HycE, the large subunit of the hydrogenase 3 from Escherichia coli 3.4.23.51 precursor of the large subunit of hydrogenase 3 + H2O HycI is an endopeptidase that is responsible for the C-terminal cleavage of the large subunit of hydrogenase 3 in Escherichia coli (UniProt: A1AER2) 3.4.23.51 precursor of the large subunit of hydrogenase 3 + H2O the final step of maturation of [NiFe]-hydrogenases involves the activity of an endopeptidase which removes an oligopeptide from the C-terminus of the large subunit. The proteolytic maturation is followed by a conformational change, closing of the metal centre, its assembly with the small hydrogenase subunit and finally in the appearance of enzyme activity. HycI is specific for hydrogenase 3 maturation