Open AccessCytochrome c oxidase is three‐copper, two‐heme‐A protein
Author(s) -
STEFFENS Guy C. M.,
BIEWALD Rosemarie,
BUSE Gerhard
Publication year - 1987
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1987.tb11057.x
Subject(s) - paracoccus denitrificans , thermus thermophilus , heme a , cytochrome c oxidase , copper , chemistry , electron transport complex iv , protein subunit , oxidase test , cytochrome , metalloprotein , copper protein , zinc , crystallography , biochemistry , enzyme , organic chemistry , escherichia coli , gene
Metal contents of preparations of procaryotic ( Paracoccus denitrificans ) and eucaryotic (beef heart) cytochome c oxidases have been determined by inductively coupled plasma atomic emission spectroscopy and shown to be stoichiometrically related to the protein contents. The results show that oxidases which possess subunits I and II have three copper atoms besides hemes a and a 3 ( Paracoccus denitrificans , Cu: 2.97 ± 0.08 and Fe: 2.09 ± 0.10; bovine heart, Cu: 2.83 ± 0.07 and Fe: 1.94 ± 0.12). Together with data reported for the c 1 aa 3 oxidase from Thermus thermophilus , the following conclusions can be drawn. Subunit I binds two copper atoms and both hemes a and a 3 and thus is the universal terminal oxidase of this spectral type. Subunit II binds one copper and functions as an electron conductor. The mitochondrial respiratory complex IV binds, in addition to three copper and two hemes a , stoichiometric amounts of magnesium and zinc (bovine heart Mg: 0.98 ± 0.05 and Zn: 1.01 ± 0.04).