Question

Treatment of antibodies with a particular protease clips the heavy chains in half, releasing the two arms of the Y-shaped molecule. How might the antibodies continue to function?

Short answer

Antibodies treated with a specific protease have their heavy chains clipped in half, releasing the two arms of the Y-shaped molecule. Because of this, the antigen-binding site is intact; the antibody fragments may destroy viruses and bacteria.

Step-by-step solution

Antibodies

An antibody (also called an immunoglobulin) is a giant protein shaped like a Y, which binds to bacteria and viruses. When the immune system senses an antigen, which is a foreign material, antibodies are produced.

Antibodies are produced by B lymphocytes or B cells, which are specialized white blood cells.

Protease 

Proteases are enzymes that hydrolyze peptide bonds of proteins. Proteases have a range of activities, ranging from regulatory to biochemical, digestion, apoptosis, blood clotting, and immunological activation.

Antigen binding site

An antibody's hinge region opens and closes to allow better interaction between the antibody and antigenic determinants on an antigen. Antibody fragments by using small pieces can also inhibit signaling molecules or receptors quickly.

Because fragments are not the same size as a whole antibody, they can interfere with the immune system's downstream functions. As a result of their small size, they can penetrate tumors more efficiently and reach tissues and cells that are difficult to reach.