3,3'-Diaminobenzidine

3,3'-Diaminobenzidine

Chemical structure of 3,3'-Diaminobenzidine

Planar ball-and-stick model of 3,3'-Diaminobenzidine

3,3'-Diaminobenzidine (DAB) is an organic compound that is widely used in biochemistry and histology for its role as a chromogenic substrate in immunohistochemistry and immunocytochemistry.

Chemical Properties

3,3'-Diaminobenzidine is a derivative of benzidine, with the chemical formula C₁₂H₁₄N₄. It consists of two benzene rings connected by a nitrogen bridge, with each ring bearing an amino group at the 3 position. This compound is typically used in its tetrahydrochloride form, which is more stable and soluble in water.

Applications

Immunohistochemistry

In immunohistochemistry, DAB is used as a substrate for peroxidase enzymes, such as horseradish peroxidase. When oxidized by peroxidase in the presence of hydrogen peroxide, DAB forms a brown precipitate that is insoluble in alcohol and organic solvents. This property makes it an excellent choice for staining tissues, as the precipitate remains stable during subsequent processing steps.

Immunocytochemistry

Similar to its use in immunohistochemistry, DAB is employed in immunocytochemistry to visualize the presence and location of specific antigens within cells. The brown precipitate formed by DAB oxidation provides a permanent record of antigen localization.

Safety and Handling

3,3'-Diaminobenzidine is considered a potential carcinogen and should be handled with care. Appropriate personal protective equipment (PPE) such as gloves and goggles should be worn when working with DAB. It is important to work in a well-ventilated area and to follow all safety guidelines for handling hazardous chemicals.

Related Pages

• Immunohistochemistry
• Immunocytochemistry
• Peroxidase
• Chromogenic substrate

• 3,3'-Diaminobenzidine
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  3,3'-Diaminobenzidine
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  3,3'-Diaminobenzidine molecule planar ball