title: Reaction of caa3-type terminal cytochrome oxidase from the thermophilic bacterium PS3 with oxygen and carbon monoxide at low temperatures.
abstract: Reaction of O2 and CO with a caa3-type terminal cytochrome oxidase (EC 1.9.3.1) from the thermophilic bacterium PS3 grown with high aeration was studied at low temperatures. The CO recombination at the temperature range studied (-50 degrees C to -80 degrees C) followed first-order kinetics with an activation energy of 29.3 kJ/mol (7.0 kcal/mol). In the presence of O2 at -113 degrees C the photolysed reduced form binds O2 to form an 'oxy' intermediate similar to Compound A. At a higher temperature (-97 degrees C) another intermediate, similar to Compound B, is formed as a result of electron transfer from the enzyme to the liganded O2.
mesh_terms: D002248:Carbon Monoxide / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010782:Photolysis; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D002248:Carbon Monoxide; D003576:Electron Transport Complex IV; D010100:Oxygen