The oxygen dependency of the redox state of heme and copper in cytochrome oxidase in vitro.
The oxidation-reduction state of cytochrome oxidase in isolated mitochondria at low oxygen concentrations was measured by the use of leghemoglobin as an oxygen indicator. P50 a + a3 varied with energy state as well as the respiratory rate. In contrast to heme a + a3, copper was slower to reduce than heme a + a3. The P50Cu of 8 x 10(-8)M in State 4 and 7.4 x 10(-8)M in State 3 was independent of both the energy state and the respiratory rate.
Hoshi
Y
Y
Biophysics Division, Hokkaido University, Sapporo, Japan.
Hazeki
O
O
Tamura
M
M
D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D003300:Copper / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006418:Heme / Q000378:metabolism*; D007700:Kinetics; D007874:Leghemoglobin / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011817:Rabbits
D007874:Leghemoglobin; D006418:Heme; D003300:Copper; D003576:Electron Transport Complex IV