Enzymatic cleavage of an immunoglobulin with papain and pepsin

Enzymatic digestion by papain splits an immunoglobulin molecule proximal (if viewing from the amino end) to the interchain disulfide bonds in the hinge region, creating two separate Fab fragments that can bind antigen and a functional Fc fragment, which can bind Fc receptors. Digestion by pepsin splits the molecule distal to the disulfide bond, yielding a fragment containing two joined Fab fragments, called F(ab')₂ and two nonfunctional heavy (H) chain fragments.