Glycophorin
Definition
A family of heavily sialylated red-cell glycoproteins. Glycophorin A carries M and N antigens; glycophorin B carries S and s antigens. Both extend through the membrane and present their antigen-bearing sugar chains on the outer surface.
- Type
- Red-cell membrane glycoprotein family
- Glycophorin A
- Carries M and N antigens
- Glycophorin B
- Carries S and s antigens
- Structure
- Transmembrane, heavily sialylated, surface-exposed
Common questions
How does glycophorin relate to the MNS blood group system?+
Glycophorin A and B are the carrier molecules for the MNS antigens; genetic variation in the genes encoding these proteins produces the M/N and S/s antigen differences that define a person's MNS blood type.
Why is heavy sialylation of glycophorin significant?+
The sialic acid residues give red cells their negative surface charge, helping prevent spontaneous clumping in circulation, and the same sugar chains form part of the antigenic epitopes recognised by anti-M, anti-N, anti-S and anti-s antibodies.
Is glycophorin typing still used in modern forensic serology?+
MNS and other blood group antigen typing has largely been superseded by DNA-based STR profiling for individual identification, though it can still appear in older casework, disputed paternity records, or specialised transfusion medicine contexts.
Related terms
- Antigen Degradation Rate
- The rate at which an antigen becomes undetectable on a dried stain, driven by protein denaturation, microbial protease activity, UV exposure, and...
- Antithetical Antigens
- Pairs of antigens where carrying one typically excludes the other on the same protein: C and c, E and e in the...
- Discriminating Power
- The statistical ability of a typing system to distinguish one individual from another in a given population. Expressed as the probability that...
- MNS System
- A blood group system comprising M and N antigens on glycophorin A (GYPA) and S and s antigens on glycophorin B (GYPB)....
- Rh System
- A blood group system defined by antigens on two proteins encoded by the RHD and RHCE genes on chromosome 1. The clinically...