Sodium Potassium Pump

Introduction to Sodium Potassium Pump

The tissues are made of characteristic cells that maintain their internal physiology in different ways. One of the most fascinating ways to maintain the concentration of potassium and sodium ions inside a cell is the sodium potassium pump. It is a protein present in many cells that maintain the Na-K balance between the cell and body fluids. In this section, we will discuss what the sodium potassium ATPase pump is and its functions elaborately.

What is Sodium Potassium Atpase?

Sodium potassium pump or Na K ATPase is a protein-based enzyme present in the cell membrane of the animals that manages and controls the concentration of sodium and potassium inside the cell. The full name of this electrogenic transmembrane ATPase is Sodium Potassium Adenosine Triphosphate. It has different functions in the cell physiology of animals.

As per the sodium potassium pump definition, this is a protein enzyme present in the cell membrane. It utilizes ATP as energy currency to transport Na and K ions. For every ATP molecule, it exports 3 Na+ ions and imports 2 K+ ions. It concludes that a single positively charged ion is excessively exported in every pump cycle. This pump cycle was discovered by Jens Christian Skou, a Nobel laureate, in the year 1957.

Due to his discovery, the movement of the ions inside and outside the cells became absolutely clear. In fact, the excitation process of nerve cells also depends on the action of these pumps present in the cell membrane.

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Mechanism of Sodium Potassium Pump

As per the structure of this electrogenic transmembrane ATPase, it has more affinity towards Na+. This is why it binds with 3 Na+ ions inside the cell. Due to phosphorylation, ADP is released and a change occurs in the pump. This change exposes Na+ ions in the extracellular space. ADP has more affinity towards K+ ions. When 2 K+ ions are bound with the ADP, dephosphorylation occurs releasing these ions inside the cells. It results in the formation of ATP thus repeating the process. This is how the sodium potassium ATPase pump works in the cell membrane controlling the ionic concentration.

Functions of Sodium Potassium Pump

As per cell physiology, the sodium potassium pump is of four different types in mammals. They all are isoforms but have unique tissue expressions and properties. The entire family is a part of P-Type ATPase. Here is a list of the sodium potassium pump function in the animal cells.

  • Resting Potential

Sodium potassium pump transports ions in and out of the cells. It helps in maintaining the resting potential of a cell during and after its excitation. The potential of the cell membrane is decided by maintaining a low concentration of Na and a high concentration of K inside the cell.

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  • Reversal Potential

Despite having the same charge, Na+ and K+ have differences in equilibrium potential in extracellular and intracellular concentrations. Sodium potassium pump transports ions inside and outside maintaining equilibrium for the proper functioning of different cells.

  • Transport

The Na exportation drives many secondary active transporters (transport proteins in the membrane) which are responsible for the transportation of amino acids, glucose, and important nutrients.

  • Cell Volume Control

The sodium potassium pump mechanism also helps in regulating the cell volume by maintaining cellular osmolarity. It means that the cell volume is regulated with the help of osmosis. Proper concentration of different nutrients and other organic compounds are maintained and controlled using this function.

  • Signal Transduction

Extracellular signal-transducing is also conducted with the help of sodium potassium ATPase.

  • Neuron Activity State

It has been found that the intrinsic activities of neurons are controlled by the sodium and potassium pump thus controlling the activity state.

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How Can it be Used for Drug Administration?

The Na K ATPase function can be used for designing and administering drugs to human physiology. The definition and structure of these pumps differ. It means that specific drug molecules can be targeted to particular organs for the remedy of certain ailments. For instance, cardiac glycosides target the NA-K pump present in the cells of the heart muscles.

Similarly, muscular contraction depends on the Ca++ ions. It is different from the sodium potassium pump but has similar functions. Specific drug molecules are designed to target muscles for proper acceptance and action.


From the above section, we learned that every animal cell has different types of Na K pumps that connect the intracellular and extracellular fluids. The osmotic regulation of a cell depends on these pumps.

The sodium potassium pump ratio, as mentioned above, is the prime function of this protein enzyme present in the cell membrane of different animal cells. Its functions are quite important for cellular physiology and the functioning of the tissues. By studying the structure and mode of operation of this pump, many pharmacological compounds can be designed to target specific tissues and organs for remedies.

FAQs (Frequently Asked Questions)

1. What is the Sodium Potassium Pump Structure?

Ans: As per the cytology of the cell membrane, the sodium potassium pump is a protein-based electrogenic transmembrane ATPase that connects the intracellular and extracellular fluids. It helps in maintaining the ionic concentration of the cells, their volume and is responsible for the absorption of nutrients such as glucose, amino acids, etc.

2. What is the difference between ATP and ADP?

Ans: Adenosine Triphosphate is the energy currency of animal cells. It is used by the Na K ATPase enzyme present in the cell membrane for exporting Na+ ions. Due to phosphorylation, ATP converts to ADP that kicks in K+ ions inside the cells. Due to dephosphorylation, ADP converts to ATP. This is the basic difference between ATP and ADP in this case.

3. Why is Na-K ATPase Important?

Ans: The channel between the extracellular and intracellular space is maintained by the sodium potassium pump ratio. It helps in maintaining cellular osmolarity, cellular volume, importing nutrients, exporting unnecessary materials, etc. This enzyme also serves as a selective channel for regulating the concentration of various compounds inside the cells and promotes cellular functions in different organs.