Neuramidase is an antigenic glycoprotein enzyme found on the surface of the Influenza virus.

Subtypes

Nine neuramidase subtypes are known, many occur only in various species of ducks and chickens. Subtypes N1, and N2 have been positively linked to epidemics in man.

Structure

The neuraminidase enzyme exists as a mushroom-shape projection on the surface of the influenza virus. It has a head consisting of four co-planar and roughly spherical subunits, and a hydrophobic region that is embedded within the interior of the virus' membrane. It is comprised of a single polypeptide chain that is oriented in the opposite direction to the haemagglutinin antigen. The composition of the polypeptide is a single chain of six conserved polar amino acids, followed by hydrophilic, variable amino acids.

Function

Neuraminidase cleaves terminal sialic acid residues from carbohydrate moieties on the surfaces of infected cells. This promotes the release of progeny viruses from infected cells.

Neuraminidase inhibitors

Inhibitors are used for combating the virus. They are Zanamivir and Oseltamivir.

See also

• Neuraminidase inhibitors
• Haemagglutinin