title: The reaction of cytochrome oxidase with cyanide. Preparation of the rapidly reacting form and its conversion to the slowly reacting form.
abstract: The magnitude of the slow phase of reaction of cytochrome oxidase with cyanide has been correlated with the size of the epr signal at g' = 12. This epr signal was not found in submitochondrial particles, and significant g' = 12 epr was only observed late in the purification of solubilized enzyme. The Hartzell-Beinert procedure for the purification of cytochrome oxidase (Hartzell, C.R., and Beinert, H. (1974) Biochim. Biophys. Acta 368, 318-338) has been modified so that the purified enzyme reacts in a single rapid phase with potassium cyanide and lacks the g' = 12 epr signal. This enzyme could be converted to the slowly reacting form upon incubation at low pH and/or low enzyme concentration. No procedure for the stable reversal of the process could be found. Some physical and chemical properties of the two forms of the enzyme are compared.
mesh_terms: D003486:Cyanides / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D011190:Potassium Cyanide / Q000494:pharmacology*; D011485:Protein Binding; D013053:Spectrophotometry
chemical_list: D003486:Cyanides; D003576:Electron Transport Complex IV; D011190:Potassium Cyanide