Immunoglobulin Fragments [Chemical/Ingredient] Immunoglobulin Fab Fragments [Chemical/Ingredient] C0021031 Fab Immunoglobulin Fragments D007140 Immunoglobulin Fab Fragments C7761971851729 Immunoglobulins, Fab Immunoglobulin Fab Fragments Fab Fragments M0011126 Immunoglobulins, Fab Fragment N0000169389 5724 Immunoglobulin Fab Fragment Univalent antigen-binding fragments composed of one entire IMMUNOGLOBULIN LIGHT CHAIN and the amino terminal end of one of the IMMUNOGLOBULIN HEAVY CHAINS from the hinge region, linked to each other by disulfide bonds. Fab contains the IMMUNOGLOBULIN VARIABLE REGIONS, which are part of the antigen-binding site, and the first IMMUNOGLOBULIN CONSTANT REGIONS. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.