How Do Neuraminidase Inhibitors Work

Neuraminidase inhibitors block the enzyme called neuraminidase in the influenza virus. The enzyme neuraminidase is responsible for releasing the virus from the infected cells. Therefore, the inhibition of the neuraminidase enzyme helps to stop further infection of host cells by the virus.

Neuraminidase inhibitors are a type of antiviral medication important in treating the influenza virus that causes flu.

Key Areas Covered

1. What are Neuraminidase Inhibitors
      – Definition, Features, Importance
2. How Do Neuraminidase Inhibitors Work
    – Features, Importance

Key Terms

Neuraminidase Inhibitors

What are Neuraminidase Inhibitors

Neuraminidase inhibitors (NAIs) are a type of drug that blocks neuraminidase enzymes. They are a common type of antiviral drug given against influenza. Viral neuraminidases are essential types of enzymes in the reproduction of the influenza virus. Moreover, they facilitate the viral budding from the host cell.

Figure 1: Neuraminidase

Some examples of neuraminidase inhibitors include oseltamivir (Tamiflu), laninamivir (Inavir), zanamivir (Relenza), and peramivir. Moreover, there are three types of influenza viruses: Influenza A, Influenza B, and Influenza C. Neuraminidase inhibitors act against both influenza A and Influenza B. Meanwhile, peramivir strongly binds to the neuraminidase enzyme, inhibiting the enzyme’s activation. It keeps the neuraminidase inactive for a long time in comparison to oseltamivir or zanamivir. Laninamivir is another antiviral drug that acts against influenza. It is slowly released to the respiratory tract, resulting in long-lasting antiviral activity.

However, neuraminidase inhibitor drugs have some side effects. The common side effects of neuraminidase inhibitor drugs include nausea and vomiting.

How Do Neuraminidase Inhibitors Work

Neuraminidase inhibitors are antiviral drugs important in treating influenza that is the virus causing flu. These viruses contain two types of glycoproteins important in infecting a host cell.  H protein, or hemagglutinin, is one type of glycoprotein that occurs on the protective envelope. The second type of glycoprotein is the N protein or neuraminidase. Neuraminidases are a large group of enzymes, and viral neuraminidases are the most common type of neuraminidase. The main function of viral neuraminidases is to catalyze the hydrolysis of the terminal salicylic acid residues between newly formed virions and host cell receptors. This assists the mobility of the virus.

Figure 2: Oseltamivir

Moreover, neuraminidase inhibitors are active against influenza A and B. The main function of neuraminidase inhibitors is to prevent the release of new viral particles from the infected cells. This limits the duration of the illness.   

Conclusion

In brief, there are three types of influenza viruses: influenza A, influenza B, and Influenza C. Neuraminidase inhibitors are a common type of antiviral drugs that act upon influenza A and influenza B. There are two types of glycoproteins that occur in the envelope of the virus. They are H proteins and N proteins. Normally, the influenza virus uses the H protein to bind salicylic sugars on the surface of the epithelial cells, while the N protein or neuraminidase is important for the mobility of viral particles through the mucus. Neuraminidase catalyzes the hydrolysis of the terminal salicylic acid residues between newly formed virions and the host cell receptors. This allows the mobility of the viral particles. In addition, the increased mobility helps to release the virions from the host cell. Neuraminidase inhibitors act against the neuraminidase enzymatic action to delay the release of virions from the infected cells. 

References:

1. Neuraminidase inhibitors. Osmosis.org.

Image Courtesy:

1. “Blausen 0012 AdiposeTi Neuraminidase Ribbon Diagram” By NASA – Own work (Public Domain) via Commons Wikimedia
2. “Oseltamivir” By BartVL71- Own Work (Public Domain) via Commons Wikimedia