Question

Which among the following antibodies in blood have the highest molecular weight?

Answer 1

Different types of antibodies produced by the body are like- IgA, IgM, IgE, IgG and IgD. The basic conventional antibodies are made of four polypeptides, two identical heavy chains and two identical light chains. Few of them are monomers (single unit) and some are of dimers or even more. IgG, IgD and IgE are generally monomers and hence their molecular weights are lower than that of IgA (generally dimer) and IgM (Pentamer). IgM are generally pentamers (made of 5 identical monomers) which makes it weigh around 970 kDa, which is the highest among all other antibodies.

Type of immunoglobulins	Molecular weight (kDa)
IgM	970
IgA	150- 600
IgE	190
IgG	150
IgD	150