Blood group
Blood groups are determined by the carbohydrates attached to the proteins in the glycocalyx on the surface of the red blood cells. Different oligosaccharide structure for each:
- Same basic oligosaccharide for blood group O
- A & B have extra, but different, terminal sugar
- N-acetyl-galactosamine for A, galactose for B
A sugar added by specific glycosyltransferase (GT) enzymes and the pattern is determined by which glycosyltransferase gene we carry.
There are two GT enzymes present (GTA and GTB) which are encoded for by different forms of the same gene. Blood group A produce GTA that put N-acetly-galctosamine on the surface of the red blood cells and blood group B produce GTB that put on galactose on the surface of the red blood cells [1].
In O blood group the GT is non-functional. AB blood group produces both GTA and GTB.
Oligosaccharide structure of blood group O consists of 2 galactose molecules, 1 fructose molecule and 1 N- acetyl glucoanime.
Refrences
- ↑ David Goodsell & RCSB Protein Data Bank, 2015, Website, assessed at 03/12/2015, avaliable from: http://www.rcsb.org/pdb/101/motm.do?momID=156