Fragment crystallizable region

This region allows antibodies to activate the immune system, for example, through binding to Fc receptors.

[5] The N-glycans attached to this site are predominantly core-fucosylated diantennary structures of the complex type.

In addition, small amounts of these N-glycans also bear bisecting GlcNAc and α-2,6 linked sialic acid residues.

By contrast, the Fc region of all antibodies in a class are the same for each species; they are constant rather than variable.

[6] In a new development in the field of antibody-based therapeutics, the Fc region of immunoglobulins has been engineered to contain an antigen-binding site.

An antibody digested by papain yields three fragments, two Fab fragments and one Fc fragment
An antibody digested by pepsin yields two fragments: a F(ab') 2 fragment and a pFc' fragment