Immunoglobulin
M
IgM
Immnuoglobulin M is also known as macro-immunoglobulin. It consists of five 75 monomers linked by a j-chain to form a pentamer. Each monomer consists of two light chains (K or A) and two heavy mu (fl) chains. The mu chain is about 570 amino acid residues long and has an additional domain (CH4) near the carboxyl end, As in IgA,the monomers are linked by inter heavy chain: disulphide bonds. Since IgM has 10 valencies it is very efficient in reacting with bacteria and foreign cells. Isoagglutinins of the A and B blood' groups are IgMs.
