3,3-Diaminobenzidine (DAB) tetrahydrochloride

Overview

DAB tetrahydrochloride is a water soluble form of DAB which is a derivative of benzene and is widely used in the staining of nucleic acids and proteins, particularly in IHC and HC procedures.

DAB is oxidized by hydrogen peroxide in the presence of peroxidases such as HRP. Once oxidized, DAB forms a dark brown insoluble precipitate at the reaction site to allow visualisation of the target.

This precipitate can be chelated with osmium tetroxide and the color produced can be enhanced by the addition of metals (e.g. nickel, copper, silver and cobalt).

Uses & applications

In IHC, DAB acts as a substrate for peroxidase enzymes conjugated to a primary or secondary antibody e.g. HRP-conjugated antibodies.

DAB is also used for peroxisome and mitochondrial COX activity staining and used to detect the presence and distribution of hydrogen peroxide in plants cells.

DAB also enhances staining of iron.

Chromogen staining agent widely used in IHC