Methods in Enzymology
Volume 301, 1999, Pages 353-367
Methods in Enzymology

Peroxynitrite reactions with carbon dioxide-bicarbonate

Author links open overlay panelRafaelRadiAnaDenicolaBruce A.Freeman


This chapter discusses the peroxynitrite reactions with carbon dioxide-bicarbonate. The chemical reactivities and biological actions of peroxynitrite anion (ONOO-)—the product of the radical-radical reaction between superoxide (O2.-) and nitric oxide (.NO)—can be profoundly influenced by carbon dioxide (CO2)-bicarbonate (HCO3-). This modulation of ONOO- reactivity—a key component of oxidative stress and tissue inflammatory injury—is highly influenced by the formation of a reactive nitrosoperoxocarbonate intermediate (ONOOCO2-) that alters both the chemical stability and reaction pathways of ONOO-. The importance of the CO2–HCO3- pair in modulating .NO and oxygen radical-dependent cell signaling and toxicity has been underestimated. Current evidence supports the idea that CO2–HCO3- can significantly participate in the biological reactivity and fate of not only ONOO-, but also other • NO-derived species and oxygen radicals. Thus, the CO2–HCO3- pair is a critical biological effector for ONOO-, via the formation ONOOCO2-. This reactive species is notable in that it potently redirects the biological reactivity and diffusivity of ONOO-.

[37] Peroxynitrite reactions with carbon dioxide-bicarbonate - ScienceDirect
https://www.sciencedirect.com/science/article/pii/S007668799901099X

　

CO2 impairs peroxynitrite-mediated inhibition of human caspase-3

Article in Biochemical and Biophysical Research Communications 349(1):367-71 · November 2006 with 10 Reads 

Paolo Ascenzi
Maria Marino
Università Degli Studi Roma Tre
Enea Menegatti
University of Ferrara

Peroxynitrite (ONOO-) is a transient powerful oxidant produced in vivo as the reaction of nitrogen monoxide (.NO) with superoxide (O2.-). The peroxynitrite reactivity is modulated by carbon dioxide (CO2) which enhances the peroxynitrite-mediated nitration of aromatics and partially impairs the oxidation of thiols. Here, the effect of CO2 on the peroxynitrite-mediated inhibition of human caspase-3, the execution enzyme of the apoptotic cascade, is reported. Peroxynitrite inhibits the catalytic activity of human caspase-3 by oxidizing the Sgamma atom of the Cys catalytic residue. In the absence of CO2, 1.0 equivalent of peroxynitrite inactivates 1.0 equivalent of human caspase-3. In the presence of the physiological concentration of CO2 (=1.3x10(-3) M), 1.0 equivalent of peroxynitrite inactivates only 0.38 equivalents of human caspase-3. Peroxynitrite affects the kcat value of the human caspase-3 catalyzed hydrolysis of N-acetyl-Asp-Glu-Val-Asp-7-amido-4-methylcoumarin, without altering Km. Both in the absence and presence of CO2, the reducing agent dithiothreitol does not prevent human caspase-3 inhibition by peroxynitrite and does not reverse the peroxynitrite-induced inactivation of human caspase-3. These results represent the first evidence for modulation of peroxynitrite-mediated inhibition of cysteine proteinase action by CO2, supporting the role of CO2 in fine tuning of cell processes (e.g., apoptosis).

CO2 impairs peroxynitrite-mediated inhibition of human caspase-3 | Request PDF
https://www.researchgate.net/publication/6853733_CO2_impairs_peroxynitrite-mediated_inhibition_of_human_caspase-3