Structural and Functional Properties of Antibodies

Immunoassay methods exploit the selective recognition and binding properties of antibodies for the recognition and quantitation of antigens or haptens. 

When the red blood cells are removed from whole blood, and the resulting plasma is allowed to clot, the fibrinogen may be removed to yield serum. Serum contains a variety of proteins, some of which are called globulins because their solubility properties are different from the other serum proteins. Antibodies are a subclass of serum globulins that possess selective binding properties. Antibodies are also called immunoglobulins (Ig). 

All immunoglobulins have a number of structural features in common.2 They possess two light polypeptide chains, each with an approximate molecular weight of 25 kDa, and two heavy polypeptide chains of 50 kDa each. These four chains are bound together in a single antibody molecule by disulfide bonds, and form a Y-shape with a central axis of symmetry (Fig. 5.2). The two halves of a natural immunoglobulin are identical. 

The N-terminal ends of the light polypeptide chains (L) occur near the top of the Y structure, in the so-called Fab fragments. These are the antigen-binding 

Immunoglobulin Class Adult Serum Concentration Functional Properties 

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