Pepsin is nitrated in the rat stomach, acquiring antiulcerogenic activity: A novel interaction between dietary nitrate and gut proteins

► Dietary nitrite triggers the formation of nitrating species in the acidic gastric lumen. ► Pepsinogen is nitrated in vivo in the stomach by dietary nitrite. ► The nitrating dynamics depends on the physiological status of the gastric mucosa. ► Pepsin is nitrated by a nitrite-dependent pathway at acidic pH. ► Nitration decreases pepsin function, preventing the progression of gastric ulcers.