College of Science

Normally, this works fine, but under stress, such as inflammation or a burst of energy use, oxidative stress damages cells at the genetic level.

This is because iron and H₂O₂ react in what’s known as the Fenton reaction, producing hydroxyl radicals, destructive molecules that attack DNA and RNA indiscriminately. But there’s a catch. In the presence of carbon dioxide — that pesky gas disrupting global climate systems — our cells gain a secret weapon in the form of bicarbonate which helps keep pH levels balanced.

A team of University of Utah chemists has discovered that bicarbonate doesn’t just act as a pH buffer but also alters the Fenton reaction itself in cells. Instead of producing chaotic hydroxyl radicals, the reaction instead makes carbonate radicals, which affect DNA in a far less harmful way, according to Cynthia Burrows, a distinguished professor of chemistry and senior author of a study published this week in PNAS.

“So many diseases, so many conditions have oxidative stress as a component of disease. That would include many cancers, effectively all age-related diseases, a lot of neurological diseases,” Burrows said. “We’re trying to understand cells’ fundamental chemistry under oxidative stress. We have learned something about the protective effect of CO₂ that I think is really profound.”

Co-authors include Aaron Fleming, a research associate professor, and doctoral candidate Justin Dingman, both members of the Burrows Laboratory.

“Just like opening up a can of beer. You release the CO₂ when you take your cells out of the incubator. It’s like doing experiments with a day-old glass of beer. It’s pretty flat. It has lost the CO₂, its bicarbonate buffer,” Burrows said. “You no longer have the protection of CO₂ to modulate the iron-hydrogen peroxide reaction.”

She believes bicarbonate needs to be added to ensure reliable results from such experiments.