Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comment
. 2021 Sep 28;118(39):e2112373118.
doi: 10.1073/pnas.2112373118.

Physiological cyanide concentrations do not stimulate mitochondrial cytochrome c oxidase activity

Flavia Giamogante  1 , Tito Calì  1 , Francesco Malatesta  2
Affiliations
Comment

Physiological cyanide concentrations do not stimulate mitochondrial cytochrome c oxidase activity

Flavia Giamogante et al. Proc Natl Acad Sci U S A. .
No abstract available

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interest.

Figures

Fig. 1.
Fig. 1.
(A) Effect of 1 nM and 100 μM cyanide (CN) on the respiration of rotenone- and antimycin-treated mouse liver mitochondria by using the TMPD–ascorbate system. Briefly, 20 mg of purified mitochondria were incubated with 1 nM or 100 μM KCN for 15 min in resuspension buffer (75 mM sucrose, Hepes 20 mM, 50 mM KCl, 1 mM NaH2PO4, 1 mM MgCl2, and 1 mM EGTA, pH 7.4). The respiratory activity of mouse liver mitochondria was measured with a Clark-type electrode, in an all-glass reaction chamber magnetically stirred, at 25 °C. Where indicated, 5 μM rotenone/1 μM antimycin A and 0.4 mM TMPD/5 mM ascorbate were added. The rate of O2 consumption (in units of nanomoles of O2 per minute per mg of protein) was calculated 10 to 14 s after the TMPD/ascorbate injection. Values are mean ± SEM; statistics of control vs. 1 nM is are nonsignificant while control vs. 100 μM KCN is P ≤ 0.01, one-way ANOVA. (B) Time course of scission of the SS bond in 20 μM DTNB (Ellman’s reagent) by 2 mM total cyanide at 25 °C. The buffer used was 0.1 M Na-phosphate, pH 7. The data are represented as difference spectra relative to DTNB alone. The data were filtered by singular value decomposition (6) and reconstructed with 2 s values (s1 = 4.3483, s2 = 0.4910, s2 = 0.0438). Analogous time courses were determined at 5, 8, and 11 mM total HCN. Time courses at 412 nm (slice through difference spectra) were fitted to an exponential process [y=α(1−e−kobst)]. A plot of kobs, measured at different cyanide concentrations, was linear, with a slope equal to the second-order rate constant reported herein. All calculations were carried with MathWorks MATLAB.
See this image and copyright information in PMC

Comment in

Comment on

References

    1. Randi E. B., Zuhra K., Pecze L., Panagaki T., Szabo C., Physiological concentrations of cyanide stimulate mitochondrial Complex IV and enhance cellular bioenergetics. Proc. Natl. Acad. Sci. U.S.A. 118, e2026245118 (2021). - PMC - PubMed
    1. Boyde T. R., The reaction between cyanide and the mixed disulphide of cysteine and penicillamine. J Chem Soc Perkin 1 22, 2751–2753 (1968). - PubMed
    1. Jones M. G., et al. ., A re-examination of the reactions of cyanide with cytochrome c oxidase. Biochem. J. 220, 57–66 (1984). - PMC - PubMed
    1. Wilson M. T., Antonini G., Malatesta F., Sarti P., Brunori M., Probing the oxygen binding site of cytochrome c oxidase by cyanide. J. Biol. Chem. 269, 24114–24119 (1994). - PubMed
    1. Antonini E., Brunori M., Colosimo A., Greenwood C., Wilson M. T., Oxygen “pulsed” cytochrome c oxidase: functional properties and catalytic relevance. Proc. Natl. Acad. Sci. U.S.A. 74, 3128–3132 (1977). - PMC - PubMed

MeSH terms