Aquaporin

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Aqvaporin is an integral membrane protein regulating water flow across the membrane.

Scheme of aquaporin

Function mechanism[edit | edit source]

Regardless of the temperature, water passes through the pores in membrane integral proteins - porins. These water channels are selective for the passage of water, neither solutes nor small molecules pass through them ( urea has its own specific channel).

Some of these channels are controlled chemically, for others the regulation is not yet known.

High specificity is achieved with a channel diameter of 0.2 nm (not even H+, OH- does not pass through). Water passes through a continuous stream of 2-4.109 molecules per second.

Structure[edit | edit source]

  • Molecular weight 30 kDa;
  • 6 hydrophobic sections (domains);
  • molecules form tetramers (water passes through each molecule separately);
  • 10 types of aquaporin H (AQP0–AQP9);

Occurrence[edit | edit source]

Localization A type of aqvaporin
Erythrocytes AQP1
Distal segment of nephron AQP2,3
Plexus choroideus APQ1
Lung APQ4
Salivary and lacrimal glands APQ5

Their permeability is in many cases controlled by vasopressin (AQP2).

Links[edit | edit source]

External links[edit | edit source]

References[edit | edit source]

  • LANGMEIER, Miloš. Základy lékařské fyziologie. 1. edition. Praha : Grada Publishing, a.s, 2009. 320 pp. ISBN 978-80-247-2526-0.