Carbonic Anhydrase: Overview

Carbonic anhydrase catalyzes the following reactions in a human body — the conversion of oxygen and water into carbonic acid. Next, these elements are dissociated into protons together with bicarbonate ions (“Carbonic anhydrase,” n.d.). This process is essential because, though this mechanism, a human body can use fat and sugars as fuel. Hence, this enzyme enables one of the most critical processes in a human’s body — breathing. Moreover, this enzyme regulates the pH levels and balance of fluids (“Carbonic anhydrase,” n.d.). For example, in kidneys, carbonic anhydrase aids in regulating the amount of water the organ receives by catalyzing different reactions.

The mechanism of work that this enzyme has is the following: zinc from this enzyme allows releasing a proton from a water molecule (Supuran & Nocentini, 2019). This, in turn, becomes a hydroxide ion. Next, carbon dioxide binds with the enzyme and reacts with hydroxide ion (Supuran & Nocentini, 2019). As a result, carbon dioxide transforms into bicarbonate ion. The catalytic site regenerates, and the process continues with another molecule of water being bound, and a similar reaction occurs.

One can find this enzyme in a human’s red blood cells. These cells are responsible for helping transport the oxygen, a vital element necessary to breakdown sugars and fats. Its function is to help transform the carbon dioxide, a byproduct of these reactions. Carbon dioxide is broken down into carbonic acid and bicarbonate ions (“Carbonic anhydrase,” n.d.). Moreover, when the red blood cells deliver bicarbonate ions to a person’s lungs, this enzyme helps convert it back into carbon dioxide, which an individual than breathes out. To maintain homeostasis, carbonic anhydrase converts carbon dioxide to bicarbonate ions and protons, which is the basis of the acid homeostasis.

Other organisms use this enzyme as well, for the same purpose as human bodies. For example, plants, both land, and water rely on photosynthesis for obtaining oxygen to keep their cells alive (“Carbonic anhydrase,” n.d.). Although humans and plans have a different way of obtaining and transporting oxygen and carbon dioxide, in both cases, carbonic anhydrase is vital. Plants use water in combination with carbon dioxide for fuel, similarly to the way human bodies use oxygen to transform sugars and fats to provide a person with an energy source (“Carbonic anhydrase,” n.d.). In plants, this enzyme helps use bicarbonate ions and transforms it into carbon dioxide. Apart from plants and humans, this enzyme is also found in the blood cells of other mammals (“Carbonic anhydrase,” n.d.). Here, the mechanism of action is similar to that in humans because the enzyme allows converting carbon dioxide into bicarbonate ions and other elements rapidly. However, there are three distinct classes of this enzyme – alpha, beta, and gamma; each has a different sequence and structure (“Carbonic anhydrase,” n.d.). In human beings, the alpha form of this enzyme can be found.

In my opinion, “carbonic anhydrase” was labeled as a “critical and important” enzyme by the scientists because it helps speed up the process of converting bicarbonate dioxide into carbon dioxide. Since breathing is vital for human beings, any enzymes that aid the process are also essential. If one imagines that a human body does not have carbonic anhydrase, the process of breathing and converting the carbon dioxide would be possible, but at a much slower rate. This enzyme allows the conversion rate of 10⁶ per second (Supuran & Nocentini, 2019). Moreover, the human body would be unable to maintain the acid-base homeostasis, meaning that the organs, for example, the eyes, would not receive enough water. This insufficiency would result in diseases such as glaucoma or other conditions.


Carbonic anhydrase. (n.d.). Web.

Supuran, C. & Nocentini, A. (Eds.). (2019). Carbonic anhydrase. Elsevier.