H+ and HCO3- are important in regulating pH. Hydrogen ions are acid ions and lower the pH of a solution. The pH is important for normal structure and function of proteins. In the human body bicarbonate ions help to neutralize hydrogen ions to maintain a normal pH range. A chemical reaction between carbon dioxide and water in the blood produces carbonic acid in equilibrium with hydrogen ions and bicarbonate. This produces a buffer which maintains the normal pH of the blood.