Decrease of cytochrome c oxidase protein in heart mitochondria of copper-deficient rats.
Copper deficiency has been reported to be associated with decreased cytochrome c oxidase activity, which in turn may be responsible for the observed mitochondrial impairment and cardiac failure. We isolated mitochondria from hearts of copper-deficient rats: cytochrome c oxidase activity was found to be lower than in copper-adequate mitochondria. The residual activity paralleled copper content of mitochondria and also corresponded with the heme amount associated with cytochrome aa3. In fact, lower absorption in the alpha-band region of cytochrome aa3 was found for copper-deficient rat heart mitochondria. Gel electrophoresis of protein extracted from mitochondrial membranes allowed measurements of protein content of the complexes of oxidative phosphorylation, revealing a lower content of complex IV protein in copper-deficient rat heart mitochondria. The alterations caused by copper deficiency appear to be specific for cytochrome c oxidase. Changes were not observed for F0F1ATP synthase activity, for heme contents of cytochrome c and b, and for protein contents of complexes I, III and V. The present study demonstrates that the alteration of cytochrome c oxidase activity observed in copper deficiency is due to a diminished content of assembled protein and that shortness of copper impairs heme insertion into cytochrome c oxidase.
Rossi
L
L
Department of Biology, University of Rome Tor Vergata, Italy. rossil@utovrm.it
Lippe
G
G
Marchese
E
E
De Martino
A
A
Mavelli
I
I
Rotilio
G
G
Ciriolo
M R
MR
D000818:Animals; D003300:Copper / Q000172:deficiency*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D008297:Male; D008929:Mitochondria, Heart / Q000201:enzymology*; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar
D003300:Copper; D003576:Electron Transport Complex IV