immunoglobulin constant regionmedical dictionary

That region of the immunoglobulin (antibody) molecule that is invariable in its amino acid sequence within any class of immunoglobulins. It confers the biological specificity to the ig and is grossly species specific. It comprises the c-terminus half of the light chains and three quarters or more of the heavy chains, all of the fc fragment, and the c-terminus half of the fab fragment.

(12 Dec 1998)