2,4-Dinitrochlorobenzene (DNCB) is a benzene

Benzene

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 derivative. It is an electrophilic, cytotoxic compound that is used in biochemical research involving glutathione-S-transferases (GSTs).

Uses

DNCB induces a type IV hypersensitivity

Type IV hypersensitivity

Type IV hypersensitivity is often called delayed type hypersensitivity as the reaction takes two to three days to develop. Unlike the other types, it is not antibody mediated but rather is a type of cell-mediated response....

 reaction in almost all people exposed to it, so it is used medically to assess the T cell

T cell

T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are...

 activity in patients. This is a useful diagnostic test for immunocompromised patients. It can also be used to treat warts.

DNCB is used as a substrate in GST enzyme activity assays. The molecule is conjugated to a single molecule of reduced glutathione

Glutathione

Glutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...

which then fluoresces at 340 nm. Affinity of CDNB for each class of GST varies and so it is not a good measure of activity for some forms (e.g. GSTT and GSTZ).