The immunoglobulin lacking hinge region is
Ig A
Ig G
Ig D
Ig E
Hinges contribute to flexibility of immunoglobulin molecules. They contain cysteine and proline. Cysteine provides interchain linkage.Proline cannot be incorporated into secondary structure of immunoglobulin molecules. The immunoglobulins Ig M & Ig E lack the hinge region. They have an extra domain in the constant region-Ch4
Immunology