Purification and characterization of the single-component nitric oxide reductase from Ralstonia eutropha H16

Nitric oxide (NO) reductase was purified from Ralstonia eutropha (formerly Alcaligenes eutrophus) using a two step chromatographic procedure. Unlike the common NO reductases, the enzyme consists of a single subunit of 75 kDa which contains both high-spin and low-spin heme b, but lacks heme c, One additional iron atom, probably a ferric non-heme iron, was identified per enzyme molecule, Whereas reduced cytochrome c was ineffective as electron donor, NO was reduced at a specific activity of 2.3 mu mol/min per mg of protein in the presence of 2-methyl-1,4-naphthoquinol, (C) 1999 Federation of European Biochemical Societies.