Cytochrome c oxidase maintains mitochondrial respiration during partial inhibition by nitric oxide

44Citations
Citations of this article
45Readers
Mendeley users who have this article in their library.

Abstract

Nitric oxide (NO), generated endogenously in NO-Synthase-transfected cells, increases the reduction of mitochondrial cytochrome c oxidase (CcO) at O2 concentrations ([O2]) above those at which it inhibits cell respiration. Thus, in cells respiring to anoxia, the addition of 2.5 μM L-arginine at 70 μM O2 resulted in reduction of CcO and inhibition of respiration at [O2] of 64.0±0.8 and 24.8±0.8 μM, respectively. This separation of the two effects of NO is related to electron turnover of the enzyme, because the addition of electron donors resulted in inhibition of respiration at progressively higher [O2], and to their eventual convergence. Our results indicate that partial inhibition of CcO by NO leads to an accumulation of reduced cytochrome c and, consequently, to an increase in electron flux through the enzyme population not inhibited by NO. Thus, respiration is maintained without compromising the bioenergetic status of the cell. We suggest that this is a physiological mechanism regulated by the flux of electrons in the mitochondria and by the changing ratio of O2:NO, either during hypoxia or, as a consequence of increases in NO, as a result of cell stress.

Cite

CITATION STYLE

APA

Palacios-Callender, M., Hollis, V., Frakich, N., Mateo, J., & Moncada, S. (2007). Cytochrome c oxidase maintains mitochondrial respiration during partial inhibition by nitric oxide. Journal of Cell Science, 120(1), 160–165. https://doi.org/10.1242/jcs.03308

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free