Involved in the maturation of [NiFe] hydrogenases. Involved in the biosynthesis of the Fe(CN)(2)CO cofactor. HypC delivers iron-bound CO(2) to HypD where reduction to CO probably occurs. In complex with HypD, accepts the cyanide ligand generated by HypF and HypE, and also coordinates the carbon monoxide ligand. Protein modification; [NiFe] hydrogenase maturation. Belongs to the HupF/HypC family.