Formate bound to cytochrome oxidase can be removed by cyanide and by reduction.
Using 14C-radiolabeled formate we have found that the rapid form of oxidized cytochrome oxidase can bind up to 1 mol of formate. Treatment of this formate-ligated enzyme with excess cyanide releases 97% of the radiolabel while reduction of formate-labeled enzyme with NADH+ruthenium releases 80-85% of the radioactivity. These data are most simply interpreted by assuming that formate binds to the heme iron of cytochrome a3.
Chang
K T
KT
Department of Biochemistry and Cell Biology Rice University, Houston, TX 77005-1892, USA.
Palmer
G
G
D000818:Animals; D002250:Carbon Radioisotopes; D002417:Cattle; D003486:Cyanides / Q000494:pharmacology*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005561:Formates / Q000378:metabolism*; D007700:Kinetics; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000378:metabolism
D002250:Carbon Radioisotopes; D003486:Cyanides; D005561:Formates; D009243:NAD; C030544:formic acid; D012428:Ruthenium; D003576:Electron Transport Complex IV