title: The purification and some equilibrium properties of the nitrite reductase of the bacterium Wolinella succinogenes.
abstract: The bacterium Wolinella succinogenes produces a nitrite reductase enzyme that can be purified to homogeneity in high yield by a combination of detergent extraction, hydroxyapatite chromatography and Mr fractionation. Nitrite reductase activity is found to be present in both a high- and a low-Mr fraction. The high-Mr fraction has been shown to consist of the low-Mr nitrite reductase enzyme associated with a hydrophobic 'binding protein'. The amino acid composition for both proteins is reported. The nitrite reductase enzyme shows spectral characteristics indicative of the presence of c-type haem groups. Measurements at 610 nm indicate the presence of some high-spin haem groups at neutral pH. This haem subgroup undergoes a pH-linked high-spin - low-spin transition at alkaline pH. Approximately two of the six haem groups present within the enzyme bind CO with low affinity (KD = 0.4 mM). The enzyme also shows a range of redox activities with various inorganic reagents. The enzyme has been shown to exhibit dithionite reductase, oxygen reductase and CO2 reductase activities.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001438:Bacteroidaceae / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004579:Electron Transport; D008024:Ligands; D008970:Molecular Weight; D010088:Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism; D013053:Spectrophotometry
chemical_list: D000596:Amino Acids; D008024:Ligands; D010088:Oxidoreductases; C048228:nitrite reductase (heme)