Carbonic anhydrase 4

Carbonic Anhydrase 4

Carbonic Anhydrase 4 structure

Carbonic Anhydrase 4 (CA4) is an enzyme that belongs to the carbonic anhydrase family. It plays a crucial role in the regulation of acid-base balance in various tissues and organs of the human body. CA4 is primarily found in the gastrointestinal tract, reproductive organs, and the central nervous system.

Structure

The structure of Carbonic Anhydrase 4 consists of a single polypeptide chain composed of 328 amino acids. It forms a homotetramer, meaning it consists of four identical subunits. Each subunit contains a zinc ion at its active site, which is essential for its catalytic activity.

Function

CA4 catalyzes the reversible conversion of carbon dioxide (CO2) and water (H2O) into carbonic acid (H2CO3). This reaction is crucial for maintaining the acid-base balance in tissues and organs. Carbonic acid can dissociate into bicarbonate ions (HCO3-) and hydrogen ions (H+), which are involved in various physiological processes.

In the gastrointestinal tract, CA4 is responsible for the production of bicarbonate ions, which help neutralize the acidic environment of the stomach. This process is essential for proper digestion and absorption of nutrients.

In the reproductive organs, CA4 is involved in the regulation of pH levels in the female reproductive tract. It helps create an optimal environment for sperm survival and fertilization.

In the central nervous system, CA4 is expressed in specific regions, including the choroid plexus and the cerebrospinal fluid. It is believed to play a role in the regulation of cerebrospinal fluid pH and the maintenance of brain homeostasis.

Clinical Significance

Mutations in the CA4 gene have been associated with certain diseases and disorders. For example, a mutation in CA4 has been linked to retinitis pigmentosa, a genetic disorder that causes progressive vision loss. Additionally, altered expression of CA4 has been observed in certain types of cancer, suggesting its potential as a diagnostic or therapeutic target.

See Also

• Carbonic Anhydrase
• Enzyme
• Acid-Base Balance