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Comment
. 2021 Sep 28;118(39):e2113369118.
doi: 10.1073/pnas.2113369118.

Reply to Giamogante et al.: The effect of low cyanide on O2 consumption is best observed in physiological, rather than reductionist, systems

Karim Zuhra  1 , Csaba Szabo  2
Affiliations
Comment

Reply to Giamogante et al.: The effect of low cyanide on O2 consumption is best observed in physiological, rather than reductionist, systems

Karim Zuhra et al. Proc Natl Acad Sci U S A. .
No abstract available

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Conflict of interest statement

The authors declare no competing interest.

Figures

Fig. 1.
Fig. 1.
(A) Effect of 100 µM cyanide on BSA-TNB. A stock solution of BSA (27 µM) in sodium phosphate buffer (100 mM, pH 7.0) was mixed with 1 mM DTNB and incubated in the absence of light for 30 min. The solution was then washed in a PD-10 MiniTrap G-25 desalting column, in order to wash out TNB and unreacted DTNB, thus isolating BSA-TNB, characterized by a spectral “shoulder” at 330 nm. After incubation of the protein with 100 µM cyanide (or vehicle) for 1 h, the protein sample was loaded in a desalting column in order to wash out the TNB released after cyanide incubation and the spectral profile of the samples was acquired using a Tecan Infinite M200 Pro spectrophotometer. The 330-nm band disappears after cyanide treatment, suggesting that protein–TNB disulfur is cleaved in the presence of cyanide. These findings support the notion that cyanide may interfere with protein posttranslational modifications involving disulfur bonds, such as protein S-glutathionylation. (B) Effect of oxidized glutathione on the number of total free cysteines in bovine CcOX. CcOX from bovine heart (C5499, Sigma; 5 mg/mL, in 25 mM Tris⋅HCl buffer solution, pH 7.8, with 5 mM EDTA and 39 mM n-dodecyl β-d-maltoside) was incubated with 5 mM oxidized glutathione (glutathione disulfide, GSSG) (or vehicle) at room temperature for 2 h. Next, the samples were loaded on a desalting column to wash out the excess GSSG and further incubated with 0.1 nM KCN (or vehicle) for 1 h, followed by another washing step, to wash out KCN and the released reduced glutathione (GSH). Protein samples were then incubated with 1 mM DTNB for 30 min in the absence of light to quantify free cysteines as described (10). The results show that GSSG decreases the number of protein-free cysteines, and this is partly restored by cyanide. Thus, cyanide can promote the release of cysteine-bound glutathione. Data shown as mean ± SEM of n ≥ 3. **P < 0.01 indicates an increased number of free cysteines in response to glutathione (+GSSG vs. control, CTR); #P < 0.05 indicates restoration of free cysteines by cyanide (GSSG + KCN vs. GSSG).
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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. Zuhra K., Szabo C., The two faces of cyanide: an environmental toxin and a potential novel mammalian gasotransmitter. FEBS J., 10.1111/febs.16135 (2021). - DOI - PMC - PubMed
    1. Correia S. C., et al., Cyanide preconditioning protects brain endothelial and NT2 neuron-like cells against glucotoxicity: Role of mitochondrial reactive oxygen species and HIF-1α. Neurobiol. Dis. 45, 206–218 (2012). - PubMed
    1. Giamogante F., Calì T., Malatesta F., Physiological cyanide concentrations do not stimulate mitochondrial cytochrome c oxidase activity. Proc. Natl. Acad. Sci. U.S.A. 118, 10.1073/pnas.2112373118 (2021). - DOI - PMC - PubMed
    1. Salabei J. K., Gibb A. A., Hill B. G., Comprehensive measurement of respiratory activity in permeabilized cells using extracellular flux analysis. Nat. Protoc. 9, 421–438 (2014). - PMC - PubMed

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