title: Glycophorin
text: # Glycophorin
  
  A glycophorin is a sialoglycoprotein of the membrane of a red blood cell. It is a membrane-spanning protein and carries sugar molecules. It is heavily glycosylated (60%). Glycophorins are rich in sialic acid, which gives the red blood cells a very hydrophilic-charged coat. This enables them to circulate without adhering to other cells or vessel walls.
  
  A particular mutation in Glycophorins is thought to produce a 40% reduction in risk of severe malaria.
  
  ## Identification
  
  After separation of red cell membranes by SDS-polyacrylamide gel electrophoresis and staining with periodic acid-Schiff staining (PAS), four glycophorins have been identified. These have been named glycophorin A, B, C, and D in order of the quantity present in the membrane, gylycophorin A being the most and glycophorin D the least common. A fifth (glycophorin E) has been identified within the human genome but cannot easily be detected on routine gel staining. In total, the glycophorins constitute ~2% of the total erythrocyte membrane protein mass. These proteins are also known under different nomenclatures but they are probably best known as the glycophorins.
  
  ## Family members
  
  The following four human genes encode glycophorin proteins:
  
  * Glycophorin A
  * Glycophorin B
  * Glycophorin C
  * Glycophorin E
  
  Glycophorin D is now known to be a variant of Glycophorin C.
  
  